Heater System GMC Savana I

MODEL IDENTIFICATION

GENERAL MOTORS SERIES DESIGNATION

Note. Escalade, Pickup, Sierra (Old), Suburban, Tahoe and Yukon models are referred to as "C" & "K" series while the Sierra (New) and Silverado are referred to by model name.

DESCRIPTION

System blends heated air with cooler outside air to obtain desired temperature. Major components of the system are blower motor, air inlet assembly, heater air distributor assembly, and heater control panel.

On "L", "M", "S" and "T" series, temperature control door is controlled by an electric actuator motor.

On all models except "C" and "K" series, vacuum actuators control mode valves to regulate flow of air through heater unit. On "C" and "K" series, mode valves are controlled by a cable mechanism.

Auxiliary Heater Blower Switch

A 3-speed blower switch (if equipped) is located either on instrument panel, to right of steering column or near radio, or in an overhead console near rearview mirror or above rear passengers. When switch is in OFF position, auxiliary system does not operate.

Blower Speed Selector Switch

The blower speed switch selects low, medium-low, medium-high or high blower speed.

VENT Mode

Air is directed to instrument panel outlets.

BI-LEV Mode

Air is directed to instrument panel and floor outlets. A slight amount of air is directed to defrost and side window defogger outlets.

HEAT Mode

Air is diverted to floor outlets, to heat passenger compartment. A slight amount of air is directed to windshield and side window defogger outlets.

BLEND Mode

Air is divided between instrument panel and floor outlets, with a slight amount of air going to defrost outlets.

DEF Mode

Air is directed to windshield defrost outlets. A slight amount of air is diverted to floor outlets and side window defogger outlets.

TEMPERATURE CONTROL SELECTOR

The temperature control lever or knob controls discharge air temperature in all mode positions. Full hot position provides maximum heat. Full cold position provides unheated air.

TROUBLE SHOOTING

Note. For additional trouble shooting information, see HEATER SYSTEMS, TROUBLE SHOOTING - RWD TRUCKS & VANS article.

Note. Blazer and Jimmy models are not available without air conditioning. Blower motor diagnostic procedures are the same for all "S" & "T" series vehicles with A/C-heater systems without automatic air conditioning.

Preliminary Checks

Check fuses, fusible links and circuit breakers. Replace as necessary. Ensure harness connectors are tight and free of corrosion. Ensure ground connections are clean and tight. Operate system through all functions to verify problems.

System Check

Turn ignition switch to ON position. Move front or auxiliary blower speed selector switch from low to high positions and listen for increase in blower motor speed at each switch position. Move blower speed selector switch from high to low positions and listen for decrease in blower motor speed. If blower motor is inoperative in any or all speeds, go to appropriate diagnostic procedure for front or rear auxiliary blower motor.

"L" & "M" Series (Astro & Safari)

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn ignition switch to ON position. While observing temperature control actuator driving shaft, move temperature control knob from hot setting to cold setting, and then from cold setting to hot setting. If shaft moves, go to next step. If shaft does not move, go to step 4 .
3. Electrical system is operating normally. Check that vehicle reaches operating temperature. If operating temperature is obtained, go to step 5 . If operating temperature is not obtained, go to HEATER SYSTEMS, TROUBLE SHOOTING - RWD TRUCKS & VANS article.
4. Ensure ignition switch is on. Using a test light connected to ground, backprobe temperature control actuator terminal No. 10 (Brown wire). If test light comes on, go to step 6 . If test light does not come on, go to step 7 .
5. Remove temperature door actuator and manually move door to hot and cold positions. If temperature door binds or is hard to move, go to step 16 . If temperature door moves freely, go to step 17 .
6. Disconnect temperature control actuator connector. Connect a test light between actuator connector terminal No. 7 (Black wire) and terminal No. 10 (Brown wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to step 8 . If test light does not come on, go to step 9 .
7. Repair open in Brown wire between temperature control motor and splice S224. Splice S224 is located approximately 6.5" (17 cm) from headlight switch connector, toward right side of instrument panel. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
8. Disconnect heater control module connector C3. Use a DVOM to measure resistance between ground and heater control assembly connector C3 terminal "B" (Black wire). If resistance is less than 10 ohms, go to step 10 . If resistance is greater than 10 ohms, go to step 11 .
9. Repair open in Black wire between temperature control motor and ground. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Connect a DVOM between heater control module connector C3 terminal "B" and connector C2 terminal "F" (control module side). If resistance varies between zero and 10,000 ohms, go to step 12 . If resistance does not vary between zero and 10,000 ohms, go to step 13 .
11. Repair open in Black wire between heater control module and ground. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
12. Use a DVOM to measure resistance between heater control module connector C2 terminal "F" and temperature control actuator connector terminal No. 8 (Light Blue wire). If resistance is less that 10 ohms, go to step 14 . If resistance is greater than 10 ohms, go to step 15 .
13. Replace heater control module. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
14. Replace temperature control motor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
15. Repair open in Light Blue wire between heater control module and temperature control motor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
16. Repair or replace temperature door. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
17. Repair restriction in cooling system.

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn ignition switch to ON position. Remove auxiliary heater switch and leave connector attached. Turn auxiliary heater switch to HI position. With test light connected to ground, backprobe heater and A/C control valve solenoid connector terminal "A" (Gray/Black wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Heater and A/C control valve solenoid is located in engine compartment, on lower left side of evaporator housing, behind accumulator. If test light comes on, go to next step. If test light does not come on, go to step 4 .
3. Connect a test light between heater and A/C control valve solenoid connector terminals "A" (Gray/Black wire) and "B" (Black wire). If test light comes on, go to step 5 . If test light does not come on, go to step 6 .
4. With test light connected to ground, backprobe auxiliary heater switch connector terminal "C" (Gray/Black wire). Move switch to LO, medium and HI positions. If test light comes on, go to step 7 . If test light does not come on, go to step 8 .
5. Check that vacuum supply to heater and A/C control valve solenoid is not restricted or hose is not cracked or plugged. If vacuum supply is okay, go to step 9 . If vacuum supply is not okay, go to step 10 .
6. Repair open in Black wire between heater and A/C control valve solenoid and splice S111. Splice S111 is located in engine harness, 6.7" (17 cm) from underhood fuse/relay center breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
7. Repair open in Gray/Black wire between auxiliary heater switch and heater and A/C control valve solenoid. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
8. Check for poor connection or loose terminals at auxiliary heater switch. If connections and terminals are okay, go to step 11 . If connections and terminals are not okay, go to step 14 .
9. Repair vacuum source or replace hose as necessary. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Check that vehicle reaches operating temperature and heater hoses are not restricted. If either condition exists, go to step 12 . If neither condition exists, go to step 13 .
11. Replace auxiliary heater switch. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
12. Repair vehicle as necessary. Go to HEATER SYSTEMS, TROUBLE SHOOTING - RWD TRUCKS & VANS article. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
13. Replace heater and A/C control valve solenoid. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
14. Repair poor connection or loose terminals at auxiliary heater switch. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

BLOWER MOTOR INOPERATIVE

Note. For new body style Sierra pickup, see SIERRA & SILVERADO .

"C" & "K" Series (Pickup, Escalade, Sierra, Suburban, Tahoe & Yukon)

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Remove blower motor high speed relay. Relay is located behind glove box, on heater assembly. Use a DVOM and check for continuity between relay terminals C1 and B2. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If continuity is indicated, go to step 4 . If continuity is not indicated, go to next step.
3. Replace blower motor high speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Disconnect blower motor 1-pin connector C1 (Purple wire) and 1-pin connector C2 (Black wire). Use a DVOM to check for continuity between ground and connector C2 (Black wire). If continuity is indicated, go to next step. If continuity is not indicated, go to step 8 .
5. Use a DVOM to check for continuity between connector C1 (Purple wire) and high speed relay cavity. If continuity is indicated, go to next step. If continuity is not indicated, go to step 9 .
6. Reconnect blower motor connectors. Connect a fused jumper between high speed relay cavity terminals A2 (Red wire) and C1 (Purple wire). If blower motor comes on, go to step 10 . If motor does not come on, go to next step.
7. Replace blower motor. See «BLOWER MOTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-c-k) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
8. Repair open in Black wire between blower motor and ground. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
9. Repair open in Purple wire between blower motor and blower motor high speed relay terminal C1. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Disconnect Heating, Ventilation, and Air Conditioning (HVAC) control module connector C2. Turn ignition switch to ON position. Use a DVOM to measure voltage between ground and control assembly connector C2 terminal "G" (Brown wire). If battery voltage is indicated, go to step 12 . If battery voltage is not indicated, go to next step.
11. Repair open in Brown wire between HVAC control module connector C2 terminal "G" and instrument panel fuse block. Instrument panel fuse block is located under driver's side of instrument panel. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
12. Replace HVAC control module. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-c-k) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

"G" Series (Express & Savana)

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn temperature control to full hot position. Place blower motor switch to HI position. Disconnect blower motor resistor/relay connector. Turn ignition switch to RUN position. Connect a test light between blower motor resistor/relay connector terminal "B" (Orange wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 6 .
3. Connect a test light between blower motor resistor/relay connector terminal "C" (Black wire) and battery voltage. If test light comes on, go to next step. If test light does not come on, go to step 9 .
4. Disconnect blower motor connector. Use a DVOM to check for continuity between blower motor resistor/relay terminal "F" and blower motor connector terminal "B" (Purple wire). If continuity is indicated, go to next step. If continuity is not indicated, go to step 10 .
5. Use a DVOM to check for continuity between blower motor resistor/relay terminal "C" and blower motor connector terminal "A" (Black wire). If continuity is indicated, go to step 11 . If continuity is not indicated, go to step 10 .
6. Disconnect control assembly 3-pin connector C1. Connect a test light between control assembly connector C1 terminal "A" (control assembly side) and ground. If test light comes on, go to next step. If test light does not come on, go to step 8 .
7. Disconnect control assembly 8-pin connector C2. Connect a test light between control assembly connector C1 terminal "A" and connector C2 terminal "G" (White wire). If test light comes on, go to step 12 . If test light does not come on, go to step 13 .
8. Disconnect control assembly 8-pin connector C2. Connect a test light between control assembly connector C2 terminal "E" (Brown wire) and ground. If test light comes on, go to step 12 . If test light does not come on, go to step 14 .
9. Repair open in Black wire between blower motor resistor/relay connector terminal "C" and ground. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Replace blower motor resistor/relay. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
11. Replace blower motor. See «BLOWER MOTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-g-series) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
12. Replace heater and A/C controller. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
13. Repair open in White wire between control assembly connector C1 and C2. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
14. Repair open in Brown wire between control assembly connector C2 and instrument panel fuse block HTR-A/C fuse (20-amp). Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Check that HTR-A/C fuse (20-amp) is not blown. If fuse is blown, go to step 19 . If fuse is not blown, go to next step.
3. Turn ignition switch to ON position. Disconnect front blower motor connector. Connect test light between blower motor connector terminals "A" (Purple wire ) and "B" (Black wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 5 .
4. Replace blower motor. See «BLOWER MOTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-l-m) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
5. With a test light connected to ground, probe terminal "A" (Purple wire) of blower motor connector. If test light comes on, go to next step. If test light does not come on, go to step 7 .
6. Disconnect blower motor resistor/relay pack connector. Use a DVOM to check for continuity between blower motor resistor/relay pack connector terminal "C" and ground. If continuity is indicated, go to step 8 . If continuity is not indicated, go to step 9 .
7. Reconnect blower motor resistor/relay pack and blower motor connectors. With a test light connected to ground, backprobe terminal "E" (Brown wire) of heater control module connector C2. If test light comes on, go to step 11 . If test light does not come on, go to step 10 .
8. Check for open in Black wire between blower motor and blower motor resistor/relay pack. If open circuit is found, go to step 12 . If open circuit is not found, go to step 13 .
9. Check for poor or loose connection at ground connection G100. Ground G100 is located in right front of radiator support, next to coolant reservoir. If G100 is okay, go to step 20 . If G100 is not okay, go to step 21 .
10. Repair open in Brown wire between instrument panel fuse block HTR-A/C fuse and heater control module. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
11. With test light connected to ground, backprobe terminal "G" (White wire) of heater control module connector C2. If test light comes on, go to step 15 . If test light does not come on, go to step 14 .
12. Repair open in Black wire between blower motor and blower motor resistor/relay pack. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
13. Replace blower motor resistor/relay pack. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
14. Replace heater control module. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
15. With a test light connected to ground, backprobe terminal "A" (White wire) of heater control module connector C3. If test light comes on, go to step 17 . If test light does not come on, go to next step.
16. Repair open in White wire between heater control module connectors C2 terminal "G" and C3 terminal "A". Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
17. Disconnect blower motor resistor/relay pack connector. Turn fan switch to HI position. Connect a test light between blower motor resistor/relay pack connector terminal "B" (Orange wire) and ground. If test light comes on, go to step 13 . If test light does not come on, go to next step.
18. Repair open in Orange wire between blower motor resistor/relay pack and heater control module. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
19. Locate and repair short. Replace HTR-A/C fuse (20-amp). Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
20. Repair open in Black wire between blower motor resistor/relay pack and ground connection G100. Ground G100 is located in right front of radiator support, next to coolant reservoir. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
21. Repair poor connection at G100. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

Sierra & Silverado

1. Disconnect blower motor electrical connector. Turn ignition switch to ON position. Turn mode selector knob to vent position and blower speed selector switch to a medium setting. Connect a test light between ground and blower motor connector Purple wire terminal. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 5 .
2. Connect a self-powered test light between blower motor connector Black wire terminal and ground. If test light comes on, go to next step. If test light does not come on, go to step 4 .
3. Replace blower motor. See «BLOWER MOTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-sierra-silverado) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Repair open in Black wire between blower motor connector terminal and ground. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
5. Disconnect blower motor resistor/relay assembly connector. Blower motor resistor/relay assembly is located on passenger's side of heater assembly, near blower motor. Connect a test light between ground and connector terminals "A" (Tan wire), "C" (Purple wire), or "D" (Light Blue wire). If test light comes on at any terminal, go to next step. If test light does not come on at any terminal, go to step 7 .
6. Replace blower motor resistor/relay assembly. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
7. Disconnect blower motor switch connector C2. Connect a test light between ground and blower motor switch connector terminal "B" (Brown wire). If test light comes on, go to next step. If test light does not come on, go to step 9 .
8. Replace blower motor switch. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-c-k) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
9. Repair open in Brown wire between blower motor switch and left bussed electrical center. Left bussed electrical center is located on lower driver's side of instrument panel. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

"S" & "T" Series (Blazer, Envoy, Jimmy, S-10 Pickup & Sonoma)

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system). Go to next step.
2. Check HVAC fuse (20-amp) in instrument panel fuse block. If fuse is blown, go to next step. If fuse is not blown, go to step 4.
3. Repair short to ground in the following circuits: See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system). Brown wire between heater controller and instrument panel fuse block. Brown wire between heater controller and blower motor resistor. Tan wire between heater controller and blower motor resistor. Light Blue wire between heater controller and blower motor resistor. Orange wire between heater controller and blower motor relay. Replace HVAC fuse (20-amp). Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
4. Turn heater controller mode knob to any position except OFF. Turn blower control knob to LO, medium-low (M1), or medium-high (M2) position. Remove blower motor relay. Relay is located on rear of engine compartment, on heater case. Turn ignition switch to ON position. Use a DVOM to measure voltage between blower motor relay connector cavity terminal No. 87A (Dark Blue wire) and ground. If battery voltage is indicated, go to next step. If battery voltage is not indicated, go to step 12.
5. Connect a fused jumper between blower motor relay connector cavity terminals No. 87A (Dark Blue wire) and No. 30 (Purple wire). If blower motor turns on, go to next step. If blower motor does not turn on, go to step 7.
6. Replace blower motor relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
7. Reconnect blower motor relay. Disconnect blower motor connector. Connect a jumper wire between blower motor terminal "A" and blower motor connector terminal "A" (Purple wire). Turn ignition switch to ON position. Turn blower control knob to HI position. Use a DVOM to measure voltage between blower motor connector terminal "A" and battery ground. If battery voltage is indicated, go to step 9. If battery voltage is not indicated, go to next step.
8. Repair open in Purple wire between blower motor and blower motor relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
9. Connect a jumper wire between blower motor terminal "B" and blower motor connector terminal "B" (Black wire). Turn ignition switch to ON position. Turn blower control knob to HI position. Use a DVOM to measure voltage between blower motor terminals "A" and "B". If battery voltage is indicated, go to next step. If battery voltage is not indicated, go to step 11.
10. Replace blower motor. See «BLOWER MOTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-s-t) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
11. Repair open in Black wire between blower motor and ground. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
12. Use a DVOM to backprobe for voltage between heater controller connector terminal "C" (Brown wire) and ground. (Scheme 1) If battery voltage is indicated, go to step 14. If battery voltage is not indicated, go to next step.
13. Repair open in Brown wire between heater controller and instrument panel fuse block. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
14. Use a DVOM to backprobe for voltage between heater controller connector C2 terminal "B" (Brown wire) and ground. If battery voltage is indicated, go to next step. If battery voltage is not indicated, go to step 16.
15. Repair open in Brown wire between heater controller connector C2 terminal "B" and connector C4 terminal "E" (Brown wire). (Scheme 1) Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
16. Replace heater controller. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).

Scheme 1

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system). Go to next step.
2. Remove blower motor high speed relay. Relay is located behind glove box, on heater assembly. Use a DVOM and check for continuity between relay terminals A2 and C1. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system). If continuity is indicated, go to step 4. If continuity is not indicated, go to next step.
3. Replace blower motor high speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
4. Connect a fused jumper between blower motor high speed relay terminal C2 and battery voltage. Connect a jumper wire between blower motor high speed relay terminal A1 and ground. Use a DVOM to check continuity between terminals A2 and C1. (Scheme 2) If continuity is indicated, go to next step. If continuity is not indicated, go to step 3.
5. Use a DVOM to check for continuity between ground and blower motor high speed relay cavity terminal A1 (Black wire). If continuity is indicated, go to step 7. If continuity is not indicated, go to next step.
6. Repair open in Black wire between blower motor high speed relay terminal A1 and ground. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
7. Use a DVOM to measure voltage between ground and blower motor high speed relay cavity terminal A2 (Red wire). If battery voltage is indicated, go to step 9. If battery voltage is not indicated, go to next step.
8. Repair open in Red wire between blower motor high speed relay terminal A2 and BLOWER fuse (50-amp) located in underhood fuse block. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
9. Disconnect Heating, Ventilation, and Air Conditioning (HVAC) control module connector C2. Use a DVOM to check for continuity between HVAC module terminals "H" and "G". Turn blower speed selector switch to HI position. If continuity is indicated, go to next step. If continuity is not indicated, go to step 11.
10. Repair open in Orange wire between HVAC control module connector terminal "H" and blower motor high speed relay connector terminal C2. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
11. Replace HVAC control module. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-c-k) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).

Scheme 2

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn temperature control to full hot position. Place blower motor switch to HI position. Disconnect blower motor resistor/relay connector. Turn ignition switch to RUN position. Connect a test light between blower motor resistor/relay connector terminal "B" (Orange wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 4 .
3. Connect a test light between resistor/relay connector terminal "A" (Red wire) and ground. If test light does not come on, go to step 5 . If test light comes on, go to step 6 .
4. Disconnect control assembly 8-pin connector C2. Use a DVOM to check for continuity between control assembly connector C2 terminals "D" and "G" (control assembly side). If continuity is indicated, go to step 7 . If continuity is not indicated, go to step 8 .
5. Replace blower motor resistor/relay assembly. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Repair open in Red wire between blower motor resistor and underhood fuse/relay center BLOWER fuse (60-amp). Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
7. Repair open in Orange wire between blower motor resistor and control assembly. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
8. Replace heater and A/C controller. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn ignition switch to ON position. Turn mode switch to OFF position. Turn blower switch to HI position. Disconnect blower motor resistor/relay pack connector. Connect a test light between ground and blower motor resistor/relay pack connector terminal "B" (Orange wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 5 .
3. Check that A/C fuse (30-amp) is not blown. If fuse is blown, go to step 8 . If fuse is not blown, go to step 9 .
4. Replace blower motor resistor/relay pack. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
5. With a test light connected to ground, backprobe terminal "D" (Orange wire) of heater control module connector. If test light comes on, go to next step. If test light does not come on, go to step 7 .
6. Repair open in Orange wire between heater control module and blower motor resistor/relay pack. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
7. Replace heater control module. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
8. Locate and repair short. Replace A/C fuse (30-amp). Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
9. Connect test light between ground and blower motor resistor/relay pack connector terminal "A" (Red wire). If test light comes on, go to step 4 . If test light does not come on, go to next step.
10. Connect a test light between ground and 5-pin Gray connector C101 terminal "E" (Red wire leading to blower motor resistor/relay pack). Connector C101 is located on left side of bulkhead, on front left side front of instrument panel. If test light comes on, go to next step. If test light does not come on, go to step 12 .
11. Repair open in Red wire between connector C101 and blower motor resistor/relay pack. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
12. Connect a test light between ground and connector C100 terminal E2 (Red wire). Connector C100 is located on left front of instrument panel. If test light comes on, go to next step. If test light does not come on, go to step 14 .
13. Repair open in Red wire between connector C100 terminal E2 and connector C101 terminal "E". Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
14. Repair open in Red wire between connector C100 terminal E2 and underhood fuse/relay center. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Disconnect blower motor resistor/relay assembly connector. Blower motor resistor/relay assembly is located on passenger's side of heater assembly, near blower motor. Connect a test light between ground and blower motor resistor/relay assembly connector terminal "F" (Orange wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Set blower motor switch to HI position. If test light comes on, go to step 5 . If test light does not come on, go to next step.
2. Check for open in Orange wire between blower motor switch connector terminal "C" and blower motor resistor/relay assembly connector terminal "F". If circuit is okay, go to step 4 . If circuit is not okay, go to next step.
3. Repair open in Orange wire. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Replace blower motor switch. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-c-k) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
5. Connect a test light between ground and blower motor resistor/relay assembly connector terminal "G" (Orange wire). If test light comes on, go to step 7 .
6. Repair open in Orange wire between blower motor resistor/relay assembly connector terminal "G" and underhood bussed electrical center. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
7. Replace blower motor resistor/relay assembly. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system). Go to next step.
2. Remove blower motor relay. Relay is located on rear of engine compartment, on heater case. Connect a test light between blower motor relay connector cavity terminal No. 86 (Orange wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system). Turn ignition switch to ON position. Turn temperature selector knob to hot position and blower control knob to HI position. If test light comes on, go to step 6. If test light does not come on, go to next step.
3. Connect a test light between heater controller 5-pin Black connector terminal "A" (Orange wire) and ground. (Scheme 3) If test light comes on, go to next step. If test light does not come on, go to step 5.
4. Repair open in Orange wire between heater controller and blower motor relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
5. Replace heater controller. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
6. Connect a test light between blower motor relay connector cavity terminals No. 86 (Orange wire) and No. 85 (Black wire). If test light comes on, go to step 8. If test light does not come on, go to next step.
7. Repair open in Black wire between blower motor relay and splice S118. Splice S118 is located in body harness, between blower motor and blower motor relay breakouts. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
8. Connect a fused jumper wire between blower motor relay connector cavity terminals No. 87 (Orange wire) and No. 30 (Purple wire). If blower motor turns on, go to next step. If blower motor does not run, go to step 10.
9. Replace blower motor relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
10. Check HVAC fuse (20-amp) located in underhood fuse block. If fuse is blown, go to step 12. If fuse is not blown, go to next step.
11. Repair open or high resistance in Orange wire between underhood fuse block and blower motor relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
12. Remove blower motor relay. Remove HVAC fuse (30-amp) from instrument panel fuse block. Connect Circuit Tester (J8681-A) between fuse terminals. If circuit breaker cycles, go to next step. If circuit breaker does not cycle, go to step 14.
13. Repair short to ground in Orange wire between blower motor relay and underhood fuse block. Replace HVAC fuse. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
14. Repair intermittent short to ground in Orange wire between blower motor relay and underhood fuse block. Replace HVAC fuse. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).

Scheme 3

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Remove blower motor high speed relay. Relay is located behind glove box, on heater assembly. Use a DVOM and check for continuity between relay terminals B2 and C1. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If continuity is indicated, go to step 4 . If continuity is not indicated, go to next step.
3. Replace blower motor high speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Disconnect blower motor resistor connector. Use a DVOM to check for continuity between blower motor resistor connector terminal "B" and blower motor high speed relay cavity terminal B2 (Dark Blue wire). If continuity is indicated, go to step 6 . If continuity is not indicated, go to next step.
5. Repair open in Dark Blue wire between blower motor resistor connector terminal "B" and blower motor high speed relay cavity terminal B2. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Disconnect HVAC control module. Using a DVOM with negative lead connected to terminal "G" of control module, check for continuity to remaining terminals on HVAC control module. Rotate switch through all blower speeds. See «BLOWER SPEED SELECTOR SWITCH TEST»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) table. If continuity is as specified, go to next step. If continuity is not as specified, go to step 8 . BLOWER SPEED SELECTOR SWITCH TEST Switch Position Continuity Between Terminals Off G & D Low G & C Medium-Low (M1) G & B Medium-High (M2) G & A High G & H
7. Replace blower motor resistor. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
8. Replace HVAC control module. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-c-k) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn temperature control to full hot position. Place blower motor switch to medium-high (M2) position. Disconnect blower motor resistor/relay connector. Turn ignition switch to RUN position. Connect a test light between blower motor resistor/relay connector terminal "F" (Light Blue wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 4 .
3. Replace blower motor resistor/relay assembly. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Disconnect control assembly 8-pin connector C2. Use a DVOM to check for continuity between control assembly connector C2 terminals "C" and "G" (control assembly side). If continuity is indicated, go to next step. If continuity is not indicated, go to step 6 .
5. Repair open in Light Blue wire between control assembly and blower motor resistor/relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Replace heater and A/C controller. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn ignition switch to ON position and move blower motor switch from OFF to LO position. If blower motor turns on, go to next step. If blower motor does not turn on, go to step 4 .
3. Move blower motor switch from LO to medium-low (M1) position. If blower motor turns on, go to step 5 . If blower motor does not turn on, go to step 6 .
4. Disconnect blower motor resistor/relay pack connector C2. Connect a test light between blower motor resistor/relay pack connector terminal "E" (Yellow wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to step 8 . If test light does not come on, go to step 7 .
5. Move blower motor switch from medium-low (M1) to medium-high (M2) position. If blower motor turns on, go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If blower motor does not turn on, go to step 9 .
6. Disconnect blower motor resistor/relay pack connector. Connect a test light between blower motor resistor/relay pack connector terminal "D" (Tan wire) and ground. If test light comes on, go to step 8 . If test light does not come on, go to step 10 .
7. With test light connected to ground, backprobe heater control module connector C2 terminal "A" (Yellow wire). If test light comes on, go to step 12 . If test light does not come on, go to step 11 .
8. Replace blower motor resistor/relay pack. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
9. Disconnect blower motor resistor/relay pack connector. Connect a test light between blower motor resistor/relay pack connector terminal "F" (Light Blue wire) and ground. If test light comes on, go to step 8 . If test light does not come on, go to step 14 .
10. With a test light connected to ground, backprobe heater control module connector C2 terminal "B" (Tan wire). If test light comes on, go to step 13 . If test light does not come on, go to next step.
11. Replace heater control module. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
12. Repair open in Yellow wire between heater control module and blower motor resistor/relay pack. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
13. Repair open in Tan wire between heater control module and blower motor resistor/relay pack. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
14. With a test light connected to ground, backprobe heater control module connector C2 terminal "C" (Light Blue wire). If test light comes on, go to next step. If test light does not come on, go to step 11 .
15. Repair open in Light Blue wire between heater control module and blower motor resistor/relay pack. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Disconnect blower motor relay. Relay is located on rear of engine compartment. on heater case. Turn ignition switch to ON position. Turn mode selector knob to heat position. Connect a fused jumper wire between blower motor relay connector cavity terminals No. 87A (Dark Blue wire) and No. 30 (Purple wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If blower motor turns on, go to next step. If blower motor does not turn on, go to step 4 .
3. Replace blower motor relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Disconnect blower motor resistor. Connect a fused jumper wire between blower motor resistor connector terminals "B" (Brown wire) and "C" (Dark Blue wire). If blower motor turns on and runs at high speed, go to step 6 . If blower motor does not turn on, go to next step.
5. Repair open or high resistance in Dark Blue wire between blower motor relay and blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Replace blower motor resistor. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Disconnect blower motor resistor/relay assembly connector C1. Connect a test light to ground and probe terminals "A", "B", "C", and "D". See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . At each terminal, turn blower speed selector switch to all medium positions. If test light comes on in all positions, go to next step. If test light does not come on in all positions, go to step 3 .
2. Replace blower motor resistor/relay assembly. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
3. Check for an open circuit in the following wires, between blower motor resistor/relay assembly and blower motor switch: Yellow wire between resistor/relay terminal "B" and switch terminal "H". Tan wire between resistor/relay terminal "A" and switch terminal "G". Light Blue wire between resistor/relay terminal "D" and switch terminal "F". Purple wire between resistor/relay terminal "E" and switch terminal "C". If circuits are okay, go to step 5 . If any circuit is faulty, go to next step.
4. Repair open in suspect circuit. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
5. Replace blower motor switch. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-c-k) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn ignition switch to ON position. Turn blower speed selector switch to medium-high (M2) position. Disconnect blower motor resistor connector. Use a DVOM to measure voltage between blower motor resistor connector terminal "D" (Light Blue wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If battery voltage is indicated, go to step 4 . If battery voltage is not indicated, go to next step.
3. Disconnect Heating, Ventilation, and Air Conditioning (HVAC) control module connector C2. Use a DVOM to check for continuity between HVAC module terminals "A" and "G". Turn blower speed selector switch to medium-high (M2) position. If continuity is indicated, go to step 6 . If continuity is not indicated, go to next step.
4. Replace blower motor resistor. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
5. Replace HVAC control module. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-c-k) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Repair open in Light Blue wire between HVAC control module C2 connector terminal "A" and blower motor resistor connector terminal "D". Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn temperature control to full hot position. Place blower motor switch to medium-high (M2) position. Disconnect blower motor resistor/relay connector. Turn ignition switch to RUN position. Connect a test light between blower motor resistor/relay connector terminal "F" (Light Blue wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 4 .
3. Replace blower motor resistor/relay assembly. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Disconnect control assembly 8-pin connector C2. Use a DVOM to check for continuity between control assembly connector C2 terminals "C" and "G" (control assembly side). If continuity is indicated, go to next step. If continuity is not indicated, go to step 6 .
5. Repair open in Light Blue wire between control assembly and blower motor resistor/relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Replace heater and A/C controller. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system). Go to next step.
2. Disconnect blower motor resistor. Connect a test light between blower motor resistor connector terminal "A" (Light Blue wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system). Turn ignition switch to ON position. Turn mode selector knob to heat position. Turn blower control knob to medium-high (M2) position. If test light comes on, go to step 4. If test light does not come on, go to next step.
3. Replace blower motor resistor. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
4. Disconnect heater controller Black 5-pin connector. (Scheme 3) Connect a test light between ground and heater controller terminal "B" (controller side). If test light comes on, go to next step. If test light does not come on, go to step 6.
5. Repair open in Light Blue wire between heater controller and blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
6. Replace heater controller. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn ignition switch to ON position. Turn blower speed selector switch to medium-low (M1) and then to LO position. Disconnect blower motor resistor connector. Use a DVOM to measure voltage between blower motor resistor connector terminal "C" (Tan wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If battery voltage is indicated, go to step 4 . If battery voltage is not indicated, go to next step.
3. Disconnect Heating, Ventilation, and Air Conditioning (HVAC) control module connector C2. Use a DVOM to check for continuity between HVAC module terminals "B" and "G". Turn blower speed selector switch to medium-low (M1) position. If continuity is indicated, go to step 6 . If continuity is not indicated, go to next step.
4. Replace blower motor resistor. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
5. Replace HVAC control module. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-c-k) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Repair open in Tan wire between HVAC control module C2 connector terminal "B" and blower motor resistor connector terminal "C". Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn temperature control to full hot position. Place blower motor switch to medium-low (M1) position. Disconnect blower motor resistor/relay connector. Turn ignition switch to RUN position. Connect a test light between blower motor resistor/relay connector terminal "D" (Tan wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 4 .
3. Replace blower motor resistor/relay assembly. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Disconnect control assembly 8-pin connector C2. Use a DVOM to check for continuity between control assembly connector C2 terminals "B" and "G" (control assembly side). If continuity is indicated, go to next step. If continuity is not indicated, go to step 6 .
5. Repair open in Tan wire between control assembly and blower motor resistor/relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Replace heater and A/C controller. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system). Go to next step.
2. Disconnect blower motor resistor. Connect a test light between blower motor resistor connector terminal "D" (Tan wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system). Turn ignition switch to ON position. Turn mode selector knob to heat position. Turn blower control knob to medium-low (M1) position. If test light comes on, go to step 4. If test light does not come on, go to next step.
3. Replace blower motor resistor. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
4. Disconnect heater controller Black 5-pin connector. (Scheme 3) Connect test light between ground and heater controller terminal "C" (controller side). If test light comes on, go to next step. If test light does not come on, go to step 6.
5. Repair open in Tan wire between heater controller and blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
6. Replace heater controller. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn ignition switch to ON position. Turn blower speed selector switch to LO position. Disconnect blower motor resistor connector. Use a DVOM to measure voltage between blower motor resistor connector terminal "A" (Yellow wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If battery voltage is not indicated, go to step 4 . If battery voltage is indicated, go to next step.
3. Replace blower motor resistor. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Disconnect HVAC control module connector C2. Use a DVOM to check for continuity between HVAC module terminals "B" and "G". Turn the blower speed selector switch to medium-low (M1) position. If continuity is indicated, go to step 6 . If continuity is not indicated, go to next step.
5. Repair open in Yellow wire between HVAC control module C2 connector terminal "C" and blower motor resistor connector terminal "A". Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Replace HVAC control module. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-c-k) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn temperature control to full hot position. Place blower motor switch to LO position. Disconnect blower motor resistor/relay connector. Turn ignition switch to RUN position. Connect a test light between blower motor resistor/relay connector terminal "E" (Yellow wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 4 .
3. Replace blower motor resistor/relay assembly. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Disconnect control assembly 8-pin connector C2. Use a DVOM to check for continuity between control assembly connector C2 terminals "A" and "G" (control assembly side). If continuity is indicated, go to next step. If continuity is not indicated, go to step 6 .
5. Repair open in Yellow wire between control assembly and blower motor resistor/relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Replace heater and A/C controller. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Disconnect blower motor resistor. Connect a test light between blower motor resistor connector terminal "B" (Brown wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Turn ignition switch to ON position. Turn mode selector knob to heat position. If test light comes on, go to step 4 . If test light does not come on, go to next step.
3. Repair open in Brown wire between blower motor resistor and splice S215. Splice S215 is located in instrument panel harness, at heater controller breakout, approximately 4" (10 cm) inside of breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Replace blower motor resistor. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Remove blower motor high speed relay. Relay is located behind glove box, on heater assembly. Turn ignition switch to ON position. Turn blower speed selector switch to OFF position. If blower motor is on, go to next step. If blower motor is not on, go to step 4 .
3. Repair short to battery voltage in Purple wire between blower motor and blower motor high speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Use a DVOM and check for continuity between relay terminals A2 and C1. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If continuity is indicated, go to next step. If continuity is not indicated, go to step 6 .
5. Replace blower motor high speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Disconnect Heating, ventilation, and Air Conditioning (HVAC) control module connector C2. Use a DVOM to measure voltage between blower motor high speed relay cavity terminal C2 (Orange wire) and ground. If reading is greater than one volt, go to next step. If reading is one volt or less, go to step 8 .
7. Repair short to voltage in Orange wire between HVAC control module connector C2 terminal "H" and blower motor high speed relay cavity terminal C2. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
8. Disconnect blower motor resistor connector. Use a DVOM to measure voltage between blower motor high speed relay cavity terminal B2 (Dark Blue wire) and ground. If reading is greater than one volt, go to next step. If reading is one volt or less, go to step 10 .
9. Repair short to voltage in Dark Blue wire between blower motor resistor connector terminal "B" and blower motor high speed relay cavity terminal B2. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Ensure HVAC control module is disconnected. Using a DVOM with negative lead connected to terminal "G" of control module, check for continuity to remaining terminals on HVAC control module. If continuity exists at any other terminal besides terminal "D", go to next step. If continuity exists only at terminal "D", go to step 12 .
11. Replace HVAC control module. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-c-k) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
12. Ensure blower motor resistor connector is disconnected. Use a DVOM with negative lead connected to ground, measure voltage at terminals "A", "C", and "D" of blower motor resistor connector. If reading is greater than 0.5 volts, go to next step. If reading is 0.5 volts or less, go to step 14 .
13. Repair short to battery voltage in suspect wire between blower motor resistor connector and HVAC control module. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
14. Replace blower motor resistor. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn mode select control to OFF position. Set blower speed switch to HI position. Disconnect blower motor resistor/relay harness connector. Turn ignition switch to ON position. Connect a test light between blower motor resistor/relay harness connector terminal "B" (Orange wire) and ground. If test light comes on, go to next step. If test light does not come on, go to step 4 .
3. Disconnect heater controller harness 3-pin connector C1. Connect a test light between heater and A/C controller connector C1 terminal "A" and ground (controller side). If test light comes on, go to step 11 . If test light does not come on, go to step 10 .
4. Connect a test light between blower motor resistor/relay connector terminal "F" (Light Blue wire) and ground. If test light comes on, go to next step. If test light does not come on, go to step 6 .
5. Disconnect heater controller harness 8-pin connector C2. Connect a test light between heater controller connector C2 terminal "C" and ground (controller side). If test light comes on, go to step 11 . If test light does not come on, go to step 13 .
6. Connect a test light between blower motor resistor/relay harness connector terminal "D" (Tan wire) and ground. If test light comes on, go to next step. If test light does not come on, go to step 8 .
7. Disconnect heater controller harness 8-pin connector C2. Connect a test light between heater controller harness connector C2 terminal "B" and ground (controller side). If test light comes on, go to step 11 . If test light does not come on, go to step 14 .
8. Connect a test light between blower motor resistor/relay harness connector terminal "E" (Yellow wire) and ground. If test light comes on, go to next step. If test light does not come on, go to step 17 .
9. Disconnect heater controller 8-pin connector C2. Connect a test light between heater controller harness connector C2 terminal "A" and ground (controller side). If test light comes on, go to step 10 . If test light does not come on, go to step 14 .
10. Disconnect heater controller harness 8-pin connector C2. Connect a test light between heater controller harness connector C2 terminal "G" (White wire) and ground. If test light comes on, go to step 16 . If test light does not come on, go to step 12 .
11. Replace heater and A/C controller. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
12. Repair short to voltage in Orange wire between heater and A/C controller and blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
13. Repair short to voltage in Light Blue wire between heater and A/C controller and blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
14. Repair short to voltage in Tan wire between heater and A/C controller and blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
15. Repair short to voltage in Yellow wire between heater and A/C controller and blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
16. Repair short to voltage in White wire between heater and A/C controller and blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
17. Replace blower motor resistor/relay assembly. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn mode control knob to OFF position. Disconnect blower motor resistor/relay pack. If blower motor continues to operate, go to next step. If blower motor turns off, go to step 4 .
3. Repair short to battery voltage in Purple wire between blower motor and resistor/relay pack. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Connect test light between ground and blower motor resistor/relay pack connector terminal "B" (Orange wire). If test light comes on, go to step 6 . If test light does not come on, go to next step.
5. Replace blower motor resistor/relay pack. See «BLOWER MOTOR RESISTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Disconnect heater control module connector. Connect a test light between heater control module connector terminal "D" (Orange wire) and ground. If test light comes on, go to step 8 . If test light does not come on, go to next step.
7. Connect a test light between ground and heater control module connector C2 terminal "G" (White wire). If test light comes on, go to step 9 . If test light does not come on, go to step 10 .
8. Repair short to battery voltage in Orange wire between heater control module connector C2 and blower motor resistor/relay pack. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
9. Repair short to battery voltage in White wire between heater control module connectors C2 and C3. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Replace heater control module. See «CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Disconnect blower motor relay. If blower motor continues to operate, go to step 4 . If blower motors stops running, go to next step.
3. Repair short to voltage in Purple wire between blower motor and blower motor relay. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Turn blower control switch to LO position. Connect a test light between ground and blower motor relay connector cavity terminal No. 86 (Orange wire). If test light comes on, go to next step. If test light does not come on, go to step 6 .
5. Repair short to voltage in Orange wire between blower motor relay and heater controller. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Replace blower motor relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

Suburban, Tahoe & Yukon

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Disconnect front auxiliary Heater, Ventilation, and Air Conditioning (HVAC) control module. Use a DVOM to check for continuity between auxiliary blower switch connector terminal "B" (Black wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If continuity is indicated, go to step 4 . If continuity is not indicated, go to next step.
3. Repair open in Black wire between auxiliary blower switch connector terminal "B" and ground. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Use a DVOM with negative lead connected to terminal "B" of front auxiliary HVAC control module and check for continuity to remaining terminals on HVAC control module. Rotate switch through all blower speeds. See «AUXILIARY CONTROL ASSEMBLY TEST»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) table. If continuity is as specified, go to step 6 . If continuity is not as specified, go to next step. AUXILIARY CONTROL ASSEMBLY TEST Switch Position Continuity Between Terminals Off None Low B & E Medium B & F High B & D
5. Replace front auxiliary HVAC control module. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Disconnect auxiliary blower motor resistor located on top of auxiliary heater unit, near right rear wheelwell. Disconnect auxiliary blower motor connector. Use a DVOM to check for continuity in Yellow wire between auxiliary blower motor resistor connector terminal "B" and auxiliary blower motor connector terminal "A". If continuity is indicated, go to step 8 . If continuity is not indicated, go to next step.
7. Repair open in Yellow wire between auxiliary blower motor resistor and auxiliary blower motor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
8. Use a DVOM to check for continuity between ground and auxiliary blower motor connector terminal "B" (Black wire). If continuity is indicated, go to next step. If continuity is not indicated, go to step 10 .
9. Replace auxiliary blower motor. See «AUXILIARY BLOWER MOTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-suburban-tahoe) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Repair open in Black wire between auxiliary blower motor and ground. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Disconnect auxiliary blower motor low speed relay. Connect a test light between blower motor low speed relay cavity terminal C1 (Red wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 8 .
3. Turn ignition switch to ON position. Connect a test light between blower motor low speed relay cavity terminal C2 (Brown wire) and ground. If test light comes on, go to next step. If test light does not come on, go to step 9 .
4. Disconnect auxiliary blower motor switch connector. Use a DVOM to check for continuity between auxiliary blower motor switch terminal "B" (Black wire) and ground. If continuity is indicated, go to next step. If continuity is not indicated, go to step 10 .
5. With auxiliary blower motor switch disconnected, connect a DVOM to check continuity between auxiliary blower motor switch terminals "B" and "E" (switch side). Turn switch to LO position. If continuity is indicated, go to next step. If continuity is not indicated, go to step 11 .
6. Disconnect auxiliary blower motor connector. Use a DVOM to check for continuity between auxiliary blower motor connector terminal "A" (Black wire) and ground. If continuity is indicated, go to next step. If continuity is not indicated, go to step 12 .
7. Disconnect auxiliary blower motor resistor connector. Use a DVOM to check for continuity between auxiliary blower motor resistor connector terminal "D" and blower motor connector terminal "B" (Yellow wire). If continuity is indicated, go to step 13 . If continuity is not indicated, go to step 14 .
8. Repair open in Red wire between underhood fuse/relay center and splice S412. Splice S412 is located about 5" (130 mm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
9. Repair open in Brown wire between instrument panel fuse block and splice S405. Splice S405 is located about 2.7" (70 mm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Repair open in Black wire between auxiliary blower motor switch and ground. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
11. Replace auxiliary blower motor switch. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
12. Repair open in Black wire between auxiliary blower motor and ground. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
13. Replace auxiliary blower motor. See «AUXILIARY BLOWER MOTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
14. Repair open in Yellow wire between auxiliary blower motor resistor and blower motor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Disconnect rear blower motor. Turn ignition switch to ON position. Turn rear blower motor switch to HI position. Connect a test light between ground and auxiliary blower motor connector terminal "A" (Yellow wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 4 .
3. Connect a test light between auxiliary blower motor connector terminals. If test light comes on, go to step 5 . If test light does not come on, go to step 6 .
4. Remove rear heater (A/C relay) from underhood fuse/relay center. Connect a test light between ground and rear heater cavity terminal A9 (Red wire). If test light comes on, go to step 7 . If test light does not come on, go to step 8 .
5. Check for poor connection or loose terminals at auxiliary blower motor connectors. If connector and terminals are okay, go to step 10 . If connector and terminals are not okay, go to step 23 .
6. Repair open in Black wire between auxiliary blower motor connector and ground. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
7. Connect a test light between ground and rear heater cavity terminal A7 (Brown wire). If test light comes on, go to step 11 . If test light does not come on, go to step 12 .
8. Check condition of RR HEAT/A/C fuse (30-amp) located in underhood fuse/relay center. If fuse is blown, go to step 24 . If fuse is okay, go to next step.
9. Repair open in Red wire between rear heater relay cavity terminal A9 and RR HEAT/A/C fuse cavity in underhood fuse/relay center. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Replace auxiliary blower motor. See «AUXILIARY BLOWER MOTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
11. Connect a test light between rear heater relay cavity terminals A7 (Brown wire) and B9 (Black wire). If test light comes on, go to step 13 . If test light does not come on, go to step 14 .
12. Repair open in Brown wire between rear heater relay cavity terminal A7 and instrument panel fuse block. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
13. Reconnect rear heater relay to underhood fuse/relay center. With a test light connected to ground, backprobe rear heater relay terminal B7 (Orange wire). If test light comes on, go to step 15 . If test light does not come on, go to step 16 .
14. Repair open in Black wire between rear heater relay cavity terminal B9 and ground. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
15. Remove auxiliary heater switch, but DO NOT disconnect. With a test light connected to ground, backprobe auxiliary heater switch connector terminal "G" (Orange wire). If test light comes on, go to step 17 . If test light does not come on, go to step 18 .
16. Replace rear heater relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
17. With a test light connected to ground, backprobe auxiliary heater switch connector terminal "A" (White wire). If test light comes on, go to step 19 . If test light does not come on, go to step 20 .
18. Repair open in Orange wire between auxiliary heater switch and rear heater relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
19. With test light connected to ground, backprobe auxiliary heater resistor pack connector terminal "B" (White wire). Auxiliary heater resistor pack is located on top of rear heater core assembly. If test light comes on, go to step 21 . If test light does not come on, go to step 22 .
20. Replace auxiliary heater switch. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
21. Repair open in Yellow wire between auxiliary heater resistor pack and auxiliary blower motor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
22. Repair open in White wire and Dark Blue wire between auxiliary heater resistor pack and auxiliary heater switch. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
23. Repair poor connection or loose terminals at blower motor connector. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
24. Locate and repair short in circuit. Replace RR HEAT/A/C fuse (30-amp). Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Remove auxiliary blower motor high speed relay. Relays are located on top of auxiliary heater unit, near right rear wheelwell. Connect a fused jumper wire between relay cavity terminals No. 1 (Red wire) and 4 (Yellow wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If auxiliary blower motor runs, go to next step. If auxiliary blower motor does not run, go to step 4 .
3. Replace auxiliary blower motor high speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Disconnect front auxiliary Heating, Ventilation, and Air Conditioning (HVAC) control module. Use a DVOM to check for continuity between terminals "B" and "D" of front auxiliary HVAC control module. Rotate switch to high position. If continuity is indicated, go to step 6 . If continuity is not indicated, go to next step.
5. Replace front auxiliary HVAC control module. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Disconnect auxiliary blower motor connector. Use a DVOM to check for continuity between auxiliary blower motor high speed relay cavity terminal No. 4 and auxiliary blower motor connector terminal "A" (Yellow wire). If continuity is indicated, go to step 8 . If continuity is not indicated, go to next step.
7. Repair open in Yellow wire between auxiliary blower motor high speed relay and auxiliary blower motor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
8. Use a DVOM to measure voltage between auxiliary blower motor high speed relay cavity terminal No. 1 (Red wire) and ground. If battery voltage is indicated, go to step 10 . If battery voltage is not indicated, go to next step.
9. Repair open in Red wire between auxiliary blower motor high speed relay and splice S401. Splice S401 is located approximately 5" (13 cm) from auxiliary blower motor connector. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Repair open in White wire between auxiliary blower motor high speed relay cavity terminal No. 2 and front auxiliary HVAC control module connector terminal "D". Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Disconnect auxiliary blower motor high speed relay. Connect a test light between blower motor high speed relay connector terminal C1 (Red wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 7 .
3. Turn ignition switch to ON position. Connect a test light between blower motor high speed relay connector terminal C2 (Brown wire) and ground. If test light comes on, go to next step. If test light does not come on, go to step 8 .
4. Disconnect auxiliary blower motor connector. Use a DVOM to check continuity between auxiliary blower motor high speed relay connector terminal A2 and auxiliary blower motor connector terminal "B" (Yellow wire). If continuity is indicated, go to next step. If continuity is not indicated, go to step 9 .
5. Set auxiliary blower motor switch to HI position. Use a DVOM to check continuity between auxiliary blower motor high speed relay connector terminal A1 (White wire, Orange wire after connector) and ground. If continuity is indicated, go to step 10 . If continuity is not indicated, go to next step.
6. Disconnect auxiliary blower motor switch connector. With auxiliary blower motor switch in HI position, use a DVOM to check continuity between auxiliary blower motor switch terminals "B" and "D" (switch side). If continuity is indicated, go to step 11 . If test light does not come on, go to step 12 .
7. Repair open in Red wire between auxiliary blower motor high speed relay and splice S412. Splice S412 is located about 5" (130 mm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
8. Repair open in Brown wire between auxiliary blower motor high speed relay and splice S405. Splice S405 is located about 2.7" (70 mm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
9. Repair open in Yellow wire between auxiliary blower motor high speed relay and splice S413. Splice S413 is located about 2.7" (70 mm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Replace auxiliary blower motor high speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
11. Repair open in Orange wire and/or White wire between auxiliary blower motor high speed relay and auxiliary blower motor switch. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
12. Replace auxiliary blower motor switch. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn ignition switch to ON position. Remove auxiliary heater switch and leave connected. Turn auxiliary heater switch to HI position. With a test light connected to ground, backprobe auxiliary heater switch connector terminal "A" (White wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 4 .
3. Repair open in White wire between auxiliary heater switch and resistor pack. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Check for poor connection or loose terminals at auxiliary heater switch. If connections and terminals are okay, go to step 6 . If connections and terminals are not okay, go to next step.
5. Replace auxiliary heater switch. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Repair poor connection at auxiliary heater switch connector. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Disconnect auxiliary blower motor resistor connector. Connect a fused jumper wire between terminals "A" (Light Blue wire) and "B" (Yellow wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Turn auxiliary HVAC control module to medium position. If auxiliary blower motor turns on, go to next step. If auxiliary blower motor does not turn on, go to step 4 .
3. Replace auxiliary blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Disconnect auxiliary blower motor connector. Use a DVOM to check for continuity in Yellow wire between auxiliary blower motor resistor connector terminal "B" and auxiliary blower motor connector terminal "A". If continuity is indicated, go to step 6 . If continuity is not indicated, go to next step.
5. Repair open in Yellow wire between auxiliary blower motor resistor and splice S402. Splice S402 is located approximately 2.5" (7 cm) from blower motor resistor harness breakout, going toward relays. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Disconnect front auxiliary HVAC control module. Use a DVOM to check for continuity between terminals "B" and "E" of front auxiliary HVAC control module with switch in low position. Check for continuity between terminals "B" and "F" of front auxiliary HVAC control module with switch in medium position. If continuity is indicated in both positions, go to step 8 . If continuity is not indicated in both positions, go to next step.
7. Replace auxiliary HVAC control module. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
8. Reconnect all disconnected components. Remove both auxiliary blower motor low and medium speed relays. Connect fused jumper wires between both relay cavity terminals No. 2 and 5. Turn auxiliary HVAC control module blower switch to low and medium positions. If blower motor operates in both positions, go to next step. If blower motor does not operate in both positions, go to step 10 .
9. Replace auxiliary blower motor low and medium speed relays. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Repair open in suspect relay circuit between cavity terminal No. 2 and auxiliary HVAC control module connector. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Disconnect auxiliary blower motor and blower motor resistor connector. Use a DVOM to check for continuity between auxiliary blower motor resistor connector terminal "D" and auxiliary blower motor connector terminal "B" (Yellow wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If continuity is indicated, go to next step. If continuity is not indicated, go to step 4 .
3. Replace blower motor resistor. See «AUXILIARY BLOWER MOTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Repair open in Yellow wire between auxiliary blower motor resistor and auxiliary blower motor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

Note. Auxiliary blower motor medium speed relay has two Red wires. Red wire, direct feed from convenience center, is hot at all times. The other Red wire is a switching wire to both auxiliary A/C-heater control assemblies.

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Remove auxiliary blower motor medium speed relay. Relays are located on top of auxiliary heater unit, near right rear wheelwell. Connect a fused jumper wire between relay cavity terminals No. 1 (Red wire) and 4 (Yellow wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If auxiliary blower motor runs, go to next step. If auxiliary blower motor does not run, go to step 4 .
3. Replace auxiliary blower motor medium speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Disconnect front auxiliary HVAC control module. Use a DVOM to check for continuity between terminals "B" and "F" of front auxiliary HVAC control module. Rotate switch to medium position. If continuity is indicated, go to step 6 . If continuity is not indicated, go to next step.
5. Replace front auxiliary HVAC control module. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Disconnect auxiliary blower resistor connector. Use a DVOM to check for continuity between terminals "A" (Light Blue wire) and "B" (Yellow wire). If continuity is indicated, go to step 8 . If continuity is not indicated, go to next step.
7. Replace auxiliary blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
8. Use a DVOM to measure voltage between auxiliary blower motor medium speed relay cavity terminal No. 1 (Red wire) and ground. If battery voltage is indicated, go to step 10 . If battery voltage is not indicated, go to next step.
9. Repair open in Red wire between auxiliary blower motor medium speed relay and splice S401. Splice S401 is located approximately 5" (13 cm) from auxiliary blower motor connector. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Repair open in Red wire between auxiliary blower motor medium speed relay cavity terminal No. 2 and auxiliary HVAC control module front connector terminal "F". Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Disconnect auxiliary blower motor medium speed relay. Connect a test light between blower motor medium speed relay connector terminal C1 (Red wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 8 .
3. Turn ignition switch to ON position. Connect a test light between blower motor medium speed relay connector terminal C2 (Brown wire) and ground. If test light comes on, go to next step. If test light does not come on, go to step 9 .
4. Disconnect auxiliary blower motor resistor harness connector. Use a DVOM to check continuity between auxiliary blower motor medium speed relay connector terminal A2 (Light Blue wire) and auxiliary blower motor resistor connector terminal "C" (Light Blue wire). If continuity is indicated, go to next step. If continuity is not indicated, go to step 10 .
5. Use a DVOM to check for continuity between auxiliary blower motor resistor terminals "C" and "D" (resistor side). If continuity is indicated, go to next step. If continuity is not indicated, go to step 11 .
6. Set auxiliary blower motor switch to medium position. Use a DVOM to check for continuity between auxiliary blower motor medium speed relay connector terminal A1 (Red wire, Tan wire after connector) and ground. If continuity is indicated, go to step 12 . If test light comes on, go to next step.
7. Disconnect auxiliary blower motor switch connector. With auxiliary blower motor switch in medium position, use a DVOM to check for continuity between auxiliary blower motor switch terminals "B" and "F" (switch side). If continuity is indicated, go to step 13 . If continuity is not indicated, go to step 14 .
8. Repair open in Red wire between auxiliary blower motor medium speed relay and splice S412. Splice S412 is located about 5" (130 mm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
9. Repair open in Brown wire between auxiliary blower motor medium speed relay and splice S405. Splice S405 is located about 2.7" (70 mm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Repair open in Light Blue wire between auxiliary blower motor medium speed relay and auxiliary blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
11. Replace auxiliary blower motor resistor. See «AUXILIARY BLOWER MOTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
12. Replace auxiliary blower motor medium speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
13. Repair open in Tan wire and/or Red wire between auxiliary blower motor high speed relay and auxiliary blower motor switch. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
14. Replace auxiliary blower motor switch. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn ignition switch to ON position. Remove auxiliary heater switch and leave connected. Turn auxiliary heater switch to medium position. With a test light connected to ground, backprobe auxiliary heater switch connector terminal "B" (Red wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 4 .
3. Check for poor connection or loose terminals at auxiliary resistor pack. Auxiliary resistor pack is located on top of auxiliary heater case. If connections and terminals are okay, go to step 9 . If connections and terminals are not okay, go to step 5 .
4. With a self-powered test light connected to ground, backprobe auxiliary heater switch connector terminal "B" (Red wire). If test light comes on, go to step 6 . If test light does not come on, go to step 7 .
5. Replace auxiliary resistor pack. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Repair open in Red wire between auxiliary heater switch and resistor pack. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
7. Check for poor connection or loose terminals at auxiliary heater switch. If connections and terminals are okay, go to step 10 . If connections and terminals are not okay, go to next step.
8. Replace auxiliary heater switch. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
9. Repair poor connection at auxiliary resistor pack connector. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Repair poor connection at auxiliary heater switch connector. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Remove auxiliary blower motor low speed relay. Relays are located on top of auxiliary heater unit, near right rear wheelwell. Connect a fused jumper wire between relay cavity terminals No. 1 (Red wire) and 4 (Yellow wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If auxiliary blower motor runs, go to next step. If auxiliary blower motor does not run, go to step 4 .
3. Replace auxiliary blower motor low speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Disconnect front auxiliary Heating, Ventilation, and Air Conditioning (HVAC) control module. Use a DVOM to check for continuity between terminals "B" and "E" of front auxiliary HVAC control module. Rotate switch to low position. If continuity is indicated, go to step 6 . If continuity is not indicated, go to next step.
5. Replace front auxiliary HVAC control module. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Disconnect auxiliary blower resistor connector. Use a DVOM to check for continuity between terminals "B" (Yellow wire) and "C" (Yellow wire). If continuity is indicated, go to step 8 . If continuity is not indicated, go to next step.
7. Replace auxiliary blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
8. Use a DVOM to measure voltage between auxiliary blower motor low speed relay cavity terminal No. 1 (Red wire) and ground. If battery voltage is indicated, go to step 10 . If battery voltage is not indicated, go to next step.
9. Repair open in Red wire between auxiliary blower motor low speed relay and splice S401. Splice S401 is located approximately 5" (13 cm) from auxiliary blower motor connector. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Repair open in Dark Blue wire between auxiliary blower motor medium speed relay cavity terminal No. 2 and auxiliary HVAC control module front connector terminal "E". Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Disconnect auxiliary blower motor low speed relay. Connect a test light between blower motor low speed relay connector terminal C1 (Red wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 8 .
3. Turn ignition switch to ON position. Connect a test light between blower motor low speed relay connector terminal C2 (Brown wire) and ground. If test light comes on, go to next step. If test light does not come on, go to step 9 .
4. Disconnect auxiliary blower motor resistor connector. Use a DVOM to check continuity between auxiliary blower motor low speed relay connector terminal A2 and auxiliary blower motor resistor connector terminal "A" (Yellow wire). If continuity is indicated, go to next step. If continuity is not indicated, go to step 10 .
5. Connect a DVOM between auxiliary blower motor resistor terminals "A" and "C" (resistor side). Resistance should be about 3 ohms. If reading is 3 ohms or less, go to next step. If resistance is significantly greater than 3 ohms, go to step 11 .
6. Set auxiliary blower motor switch to LO position. Use a DVOM to check continuity between auxiliary blower motor low speed relay connector terminal A1 (Dark Blue wire, Yellow wire after connector) and ground. If continuity is indicated, go to step 12 . If continuity is not indicated, go to next step.
7. Disconnect auxiliary blower motor switch connector. With auxiliary blower motor switch in LO position, use a DVOM to check continuity between auxiliary blower motor switch terminals "B" and "E" (switch side). If continuity is indicated, go to step 13 . If continuity is not indicated, go to step 14 .
8. Repair open in Red wire between auxiliary blower motor low speed relay and splice S412. Splice S412 is located about 5" (130 mm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
9. Repair open in Brown wire between auxiliary blower motor low speed relay and splice S405. Splice S405 is located about 2.7" (70 mm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Repair open in Yellow wire between auxiliary blower motor low speed relay and auxiliary blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
11. Replace auxiliary blower motor resistor. See «AUXILIARY BLOWER MOTOR»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
12. Replace auxiliary blower motor low speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
13. Repair open in Yellow wire and/or Dark Blue wire between auxiliary blower motor high speed relay and auxiliary blower motor switch. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
14. Replace auxiliary blower motor switch. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn ignition switch to ON position. Remove auxiliary heater switch and leave connected. Turn auxiliary heater switch to LO position. With a test light connected to ground, backprobe auxiliary heater switch connector terminal "C" (Dark Blue wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to next step. If test light does not come on, go to step 4 .
3. Check for poor connection or loose terminals at auxiliary resistor pack. Auxiliary resistor pack is located on top of auxiliary heater case. If connections and terminals are okay, go to step 9 . If connections and terminals are not okay, go to step 5 .
4. With a self-powered test light connected to ground, backprobe auxiliary heater switch connector terminal "F" (Dark Blue wire). If test light comes on, go to step 6 . If test light does not come on, go to step 7 .
5. Replace auxiliary resistor pack. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
6. Repair open in Dark Blue wire between auxiliary heater switch and resistor pack. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
7. Check for poor connection or loose terminals at auxiliary heater switch. If connections and terminals are okay, go to step 10 . If connections and terminals are not okay, go to next step.
8. Replace auxiliary heater switch. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
9. Repair poor connection at auxiliary resistor pack connector. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
10. Repair poor connection at auxiliary heater switch connector. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Remove auxiliary blower motor relays one at a time. Note when blower motor stops, and which relay was removed. If blower motor stops, go to next step. If blower motor does not stop after all relays are removed, go to step 4 .
3. Replace suspect relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. With all relays removed, use a DVOM to measure voltage between ground and auxiliary blower motor high speed relay cavity terminal No. 4 (Yellow wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If reading is one volt or less, go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If reading is greater than one volt, go to next step.
5. Repair short to battery voltage in Yellow wire between auxiliary blower motor, auxiliary blower motor resistor and auxiliary blower motor high speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Disconnect auxiliary blower motor and auxiliary blower motor resistor connector. Disconnect auxiliary blower motor high, medium and low speed relays. Turn ignition switch to ON position. Connect a test light between auxiliary blower motor harness connector terminal "B" (Yellow wire) and ground. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to step 13 . If test light does not come on, go to next step.
3. Connect a test light between auxiliary blower motor resistor connector terminal "A" (Yellow wire) and ground. If test light comes on, go to step 14 . If test light does not come on, go to next step.
4. Connect a test light between auxiliary blower motor resistor connector terminal "C" (Light Blue wire) and ground. If test light comes on, go to step 15 . If test light does not come on, go to next step.
5. Reconnect auxiliary blower motor resistor and blower motor connectors. Reconnect auxiliary blower motor low speed relay. If auxiliary blower motor operates, go to next step. If auxiliary blower motor does not operate, go to step 8 .
6. Disconnect auxiliary blower motor switch connector. If auxiliary blower motor stops running, go to step 16 . If auxiliary blower motor continues to operate, go to next step.
7. Disconnect auxiliary blower motor low speed relay. Use a DVOM to check continuity between auxiliary blower motor low speed relay connector terminal A1 (Dark Blue wire; Yellow wire after connector) and ground. If continuity is indicated, go to step 17 . If test light does not come on, go to step 18 .
8. Reconnect auxiliary blower motor medium speed relay. If auxiliary blower motor operates, go to next step. If auxiliary blower motor does not operate, go to step 11 .
9. Disconnect auxiliary blower motor switch connector. If auxiliary blower motor stops running, go to step 16 . If auxiliary blower motor continues to operate, go to next step.
10. Disconnect auxiliary blower motor medium speed relay. Use a DVOM to check continuity between auxiliary blower motor medium speed relay connector terminal A1 (Red wire, Tan wire after connector) and ground. If continuity is indicated, go to step 19 . If continuity is not indicated, go to step 20 .
11. Disconnect auxiliary blower motor switch connector. Use a DVOM to check continuity between auxiliary blower motor switch connector terminal "D" (Orange wire) and auxiliary blower high speed relay connector terminal A1 (White wire). If continuity is indicated, go to step 21 . If continuity is not indicated, go to next step.
12. Disconnect auxiliary blower motor switch connector. Use a DVOM to check for continuity between auxiliary blower motor switch terminals "B" and "D". If continuity is indicated, go to step 16 . If continuity is not indicated, go to step 22 .
13. Repair short to battery voltage in Yellow wire between auxiliary blower motor resistor, auxiliary blower motor high speed relay and auxiliary blower motor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
14. Repair short to battery voltage in Yellow wire between auxiliary blower motor low speed relay and auxiliary blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
15. Repair short to battery voltage in Light Blue wire between auxiliary blower motor medium speed relay and auxiliary blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
16. Replace auxiliary blower motor switch. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
17. Repair short to ground in Yellow/Dark Blue wire between auxiliary blower motor switch and auxiliary blower motor low speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
18. Replace auxiliary blower motor low speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
19. Repair short to ground in Tan/Red wire between auxiliary blower motor switch and auxiliary blower motor medium speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
20. Replace auxiliary blower motor medium speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
21. Repair short to ground in Orange/White wire between auxiliary blower motor switch and auxiliary blower motor high speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
22. Replace auxiliary blower motor high speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . Go to next step.
2. Turn ignition switch to ON position. Disconnect auxiliary heater switch connector. If blower motor continues to run, go to next step. If blower motor stops running, go to step 4 .
3. Replace auxiliary heater switch. See «AUXILIARY CONTROL ASSEMBLY»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
4. Disconnect auxiliary resistor pack connector. If blower motor continues to run, go to next step. If blower motor stops running, go to step 6 .
5. Connect a test light between ground and auxiliary heater switch connector terminal "B" (Red wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) . If test light comes on, go to step 7 . If test light does not come on, go to step 8 .
6. Repair short to battery voltage in White wire or Yellow wire between auxiliary blower motor and auxiliary heater switch. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
7. Repair short to battery voltage in Red wire between auxiliary heater switch and resistor pack. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
8. Repair short to battery voltage in Dark Blue wire between auxiliary heater switch and resistor pack. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .

REMOVAL & INSTALLATION

Removal & Installation ("C" & "K" Series - Pickup, Escalade, Sierra, Suburban, Tahoe & Yukon)

1. Disconnect negative battery cable. Remove glove box. Remove front screw from right door sill plate. Remove passenger's kick panel. Unplug connector from Electronic Control Module (ECM) if necessary. Unplug connector from blower motor. Remove blower motor cover and cooling tube.
2. Remove bolt from right instrument panel pivot support. Remove blower motor flange screws. Pull blower motor forward carefully to avoid distorting blower fan. Remove blower motor. To install, reverse removal procedure.

Removal & Installation ("G" Series)

Open hood. Disconnect negative battery cable. Unplug blower motor connector. Remove screws and blower motor. To install, reverse removal procedure.

Removal & Installation ("L" & "M" Series)

Disconnect negative battery cable. Unplug blower connector. Remove coolant recovery and washer fluid reservoir assembly. Remove screws that retain blower motor cover. Cut insulation cover between outlined ribs. Retain insulation cover for installation. Remove cooling tube from blower motor. Remove screws and blower motor from heater case. To install, reverse removal procedure.

Scheme 4

Removal & Installation (Sierra & Silverado)

Disconnect blower motor resistor connector and remove screws attaching blower motor insulating cover to heater assembly. Disconnect blower motor connector. Pull retaining tab for blower motor downward and rotate blower motor counterclockwise to remove blower motor from heater assembly. To install, reverse removal procedure.

Removal & Installation ("S" & "T" Series)

1. Disconnect negative battery cable. On S-10 and Sonoma, remove powertrain or vehicle control module. Remove coolant reservoir. Remove blower motor cooling tube. Unplug connector. Remove blower motor.
2. On Blazer and Jimmy, remove powertrain or vehicle control module from engine compartment to allow access to blower motor. Remove coolant reservoir. Remove blower motor cover retaining screws.
3. Cut blower motor cover along indicated cut line using razor or sharp utility knife. Tear the remaining part of the cover, beginning with the upper portion. Remove blower motor cooling tube. Unplug connector. Remove blower motor. To remove blower motor resistor, cut out cover and remove screws retaining blower motor resistor.
4. To install, reverse removal procedure. On Blazer and Jimmy, seal cut lines with black weatherstrip adhesive before installing cover.

Scheme 5

1. Disconnect negative battery cable. Roll instrument panel back far enough to access top of heater case and blower motor resistor. See «HEATER CORE»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__removal-installation-c-k).
2. Remove relay bracket and disconnect blower motor resistor. Remove screws attaching blower motor to heater case and remove resistor. (Scheme 9) To install, reverse removal procedure.

Open hood. Disconnect negative battery cable. Remove blower motor resistor/relay assembly and blower motor connectors. Blower motor resistor/relay assembly is located near blower motor, on firewall. Remove blower motor retaining screws. Remove resistor/relay assembly from blower motor case. To install, reverse removal procedure.

Disconnect negative battery cable. Remove coolant recovery and washer fluid reservoir assembly. Disconnect blower motor resistor connector. Remove screws retaining blower motor resistor to top of heater case. To install, reverse removal procedure.

Disconnect blower motor and blower motor resistor/relay assembly connectors. Remove screws attaching resistor/relay to top of heater assembly near blower motor. To install, reverse removal procedure.

On Blazer and Jimmy, see BLOWER MOTOR . On S-10 and Sonoma, remove electrical connector from resistor and remove screws retaining resistor to heater case. Remove resistor. To install, reverse removal procedure.

Removal & Installation ("C" & "K" Series - Pickup, Escalade, Sierra, Silverado, Suburban, Tahoe & Yukon)

1. Disconnect negative battery cable. Tilt steering column to lowest position. Remove instrument panel bezel by pulling outward to disengage clips. Disconnect electrical connectors from bezel. Using a small screwdriver, release radio assembly snap-fit retainers. Disconnect electrical connectors and remove radio.
2. Release control assembly snap-fit retainers. Pull control assembly away from instrument panel. Disconnect control cables. Unplug connectors. Remove control assembly. Remove blower switch knob and retaining clip. Remove blower switch. To install, reverse removal procedure.

1. Disconnect negative battery cable. Ensure parking brake is set. Place steering column shift lever into first gear. Remove instrument panel bezel by pulling at lower left, then lower right, then from top to release retainers. Disconnect electrical connectors and remove bezel. Rotate bezel counterclockwise to remove.
2. Remove control assembly screws and pivot assembly to remove right side tab. Pull control assembly away from instrument panel. Disconnect electrical and vacuum connectors. Remove control assembly. To install, reverse removal procedure.

1. Disconnect negative battery cable. Set parking brake and set transmission to low gear position. Grasp edges of instrument panel bezel and pull firmly outward to remove. Disconnect electrical connectors and remove bezel.
2. Remove control panel retaining screws. Pivot control assembly away from instrument panel to access rear of panel. Disconnect electrical connectors. Disconnect vacuum connectors. Remove control assembly. To install, reverse removal procedure.

Scheme 6

Scheme 7

1. Remove left underdash hush panel. Remove 4 screws attaching knee bolster below steering column. Set parking brake. Disconnect emergency brake release cable from ratchet mechanism. Move tilt steering column down (if equipped). Turn ignition key to ON position and move automatic transmission gear selector to low (if equipped).
2. Disconnect electrical connectors and remove instrument panel accessory trim plate. (Scheme 17) Remove heater control assembly retaining screws. Remove heater control assembly. Unplug vacuum connectors. Unplug electrical connectors. To install, reverse removal procedure.

1. Disconnect negative battery cable. Remove instrument panel bezel. Remove control assembly screws. Disconnect cables from control assembly. (Scheme 8)
2. Remove glove box and glove box door as an assembly. Remove driver's lower instrument panel cover and knee bolster. Lower steering column. Remove instrument panel left and right pivot bolts located at lower corners of instrument panel. Remove 3 screws from defroster vent near windshield.
3. Disconnect any connectors and tilt instrument panel back far enough to access temperature and mode control cables. Remove cable retaining clip. Disconnect cables. To install, reverse removal procedure. Check cable operation.

Scheme 8

Disconnect negative battery cable. Tilt steering wheel to lowest position and pull outward on instrument panel bezel to disengage clips. Using a small screwdriver, release control radio and assembly snap-fit retainers. Pull control assembly and radio away from instrument panel. Disconnect electrical connectors and control cables. Remove screws and remove mode and temperature cables from side of heater module. To install, reverse removal procedure.

HEATER CORE

Note. On "C" and "K" series, heater core may be accessible without removing heater case. Remove passenger's side door sill plate and kick panel. Pull passenger's side of carpet back enough to access bolt at rear of heater case cover plate. If all heater case cover plate screws are accessible, begin procedure at step 3).

Removal & Installation ("C" & "K" Series)

1. Disable air bag system. See AIR BAG SYSTEM SAFETY article in GENERAL INFORMATION. Disconnect negative battery cable. Remove glove box by squeezing sides together. Remove 2 instrument panel retaining bolts from glove box opening. Remove center floor duct. Remove center support bolt. Remove Electronic Control Module (ECM) and tray. Remove both kick panels. Remove blower motor cover and blower motor.
2. Remove driver's lower instrument panel cover and knee bolster. Lower steering column. Remove instrument panel left and right pivot bolts located at lower corners of instrument panel. Remove 3 screws from defrost vent, near windshield. Disconnect any connectors and tilt instrument panel back far enough to access heater case. Remove coolant recovery reservoir from engine compartment. Drain engine coolant. Disconnect heater hoses at core. Remove bolts and nuts from engine compartment attaching heater case to vehicle. Remove heater case.
3. Remove 7 screws attaching heater case cover plate. Remove screws and bracket attaching core to case. (Scheme 9) Remove heater core. To install, reverse removal procedure. Replace any seals. Fill cooling system. Start engine and check for leaks.

Scheme 9

1. Disconnect battery cables, and remove battery. Drain engine coolant. Remove coolant recovery overflow reservoir. Remove right kick panel. Remove center lower trim plate by pulling outward. Remove right knee bolster. Remove outer floor air duct. Disconnect heater hoses at core.
2. Remove retaining screws from heater case. (Scheme 10) Carefully open access door to remove retainers. Remove retainers from heater core. Remove heater core. To install, reverse removal procedure. Fill cooling system. Start engine and check for leaks.

Scheme 10

Remove Air Cleaner. Disconnect negative battery cable. Drain engine coolant. Remove heater hoses at core. Remove heater case cover screws and cover. Remove heater core retaining straps. Remove heater core. To install, reverse removal procedure. Fill cooling system. Start engine and check for leaks.

1. Disable air bag system. See AIR BAG SYSTEM SAFETY article in GENERAL INFORMATION. Disconnect heater hoses from heater core. Remove screws and remove mode and temperature cables from side of heater module. Remove instrument panel. See «INSTRUMENT PANEL»(/gmc/savana/i-1996-2002/remont/heater/#heater-system) .
2. Disconnect electrical and ground connections to heater/ventilation assembly. Remove heater/ventilation assembly mounting screws and nuts from engine compartment. Remove heater/ventilation assembly from vehicle. Remove heater core cover located between air distribution and blower motor portions of assembly. Remove heater core. To install, reverse removal procedure.

1. Disconnect negative battery cable. Drain engine coolant. Disconnect heater hoses at core. (Scheme 11) Remove instrument panel. See «INSTRUMENT PANEL»(/gmc/savana/i-1996-2002/remont/heater/#heater-system). Remove air inlet assembly.
2. Disconnect vacuum lines to heater case components. Remove heater case retaining studs from engine compartment. Disconnect blower motor resistor. Remove heater case. Remove heater core access cover from top of heater case. Remove heater core. Remove seals. To install, reverse removal procedure. Fill cooling system. Replace old seals with new seals. Start engine and check for leaks.

Scheme 11

Removal & Installation (Suburban, Tahoe & Yukon)

Disconnect negative battery cable. Remove middle and rear seats. Remove passenger's rear trim panel armrest. Remove rear door pillar trim panel. Remove rear door sill cover. Remove rear trim panel by pulling upward to release clips. Unplug electrical connector and remove blower motor. Auxiliary blower motor resistor is located on the underside of the blower motor housing. To install, reverse removal procedure.

Disconnect negative battery cable. Blower motor resistor is located next to blower motor, and can be removed without removing auxiliary heater assembly. Remove auxiliary heater assembly. See AUXILIARY HEATER CORE . Remove cover screws and cover. Unplug connector(s) from blower motor. Remove blower motor. To install, reverse removal procedure.

Disconnect negative battery cable. Heater assembly is located on left side of vehicle, forward of left rear tire. Remove middle and rear seats. Remove driver's side footwell light cover. Remove body side front lower trim panel. Unplug connector(s) from blower motor. Remove retaining screws. Remove blower motor. To install, reverse removal procedure.

Scheme 12

1. To remove front auxiliary heater control assembly, remove screws and front overhead console above rear-view mirror. Unplug connectors from control assembly. Remove screws and control assembly. To install, reverse removal procedure.
2. To remove rear auxiliary heater control assembly from rear overhead console, remove control panel bezel and control panel assembly. Disconnect electrical connectors and remove control panel. To install, reverse removal procedure.

Remove control panel bezel and control panel assembly (from front or rear overhead console). Disconnect electrical connectors and remove control panel. To install, reverse removal procedure.

Disconnect negative battery cable. Set parking brake and set transmission to low gear position. Grasp edges of instrument panel bezel and pull firmly outward to remove. Disconnect electrical connectors and remove bezel. Remove auxiliary heater switch. To install, reverse removal procedure.

Disconnect negative battery cable. Ensure parking brake is set. Place steering column shift lever into first gear. Remove instrument panel bezel. Unplug connector. Remove control switch. To install, reverse removal procedure.

Disconnect negative battery cable. Ensure parking brake is set. Place steering column shift lever into first gear. Remove instrument panel bezel by pulling at lower left, lower right, then from top to release retainers. Disconnect electrical connectors and remove bezel. Rotate bezel counterclockwise to remove. Release blower switch retaining tabs. Unplug electrical connector. Remove blower switch. To install, reverse removal procedure.

1. Disconnect negative battery cable. Drain engine coolant. Remove middle and rear seats. Remove passenger's rear trim panel armrest. Remove rear door pillar trim panel. Remove rear door sill cover. Remove rear trim panel by pulling upward to release clips. Remove right rear wheelwell panel.
2. Disconnect heater hoses from heater core. Unplug connector from heater assembly. Remove blower motor, if necessary. Remove heater case. Separate heater case halves and remove heater core. To install, reverse removal procedure. Fill cooling system. Start engine and check for leaks.

1. Disconnect negative battery cable. Drain engine coolant. Remove rear seat as necessary. Heater is located on left side of vehicle, in rear corner. Remove rear side trim panel by pulling outward to disengage clips. Remove trim panel, above rear doors, and at top and lower edge of left rear side window. Remove rear pillar panel.
2. Raise and support vehicle. Disconnect heater hoses from heater core. Remove stud from case. Lower vehicle. Remove case cover. Unplug connectors from blower motor and resistor. Remove heater case from vehicle. (Scheme 13)
3. Separate blower motor plate from heater case. Remove heater core seal, mounting strap screws, and mounting straps. Remove heater core. To install, reverse removal procedure. Fill cooling system. Start engine and check for leaks.

Scheme 13

Disconnect negative battery cable. Drain engine coolant. Heater is located on left side of vehicle, forward of left rear tire. Remove body side front lower trim panel. Disconnect heater hoses from heater core. Remove heater cover. Remove mounting straps (band clamps). Remove heater core. To install, reverse removal procedure. Fill cooling system. Start engine and check for leaks.

Scheme 14

1. Disconnect negative battery cable. Tilt steering wheel to lowest position and pull outward on instrument panel bezel to disengage clips. Using a small screwdriver, release control radio and assembly snap-fit retainers. Pull control assembly and radio away from instrument panel. Disconnect electrical connectors.
2. Remove end panels from instrument panel below side window defrost ducts. Remove air outlets from passenger's side of instrument panel, on both sides of air bag assembly, by pulling outward firmly to release clips. Reach inside of air outlet openings and depress clips attaching grab handle to instrument panel.
3. Remove door sill plates by pulling upward, kick panels, and windshield "A" pillar moldings by pulling outward to disengage retainers. Remove 4 instrument panel top cover screws and cover. (Scheme 15) Disconnect ambient light sensor from top cover. Remove cup holder and cover. Remove front seat(s) if necessary. If vehicle is equipped with center console, go to next step. If vehicle is not equipped with center console, go to step 5.
4. Open console door and remove 4 bolts at bottom of console. Remove screws attaching console extension to floor console. Remove floor console, then remove console bracket. Remove console extension insert and remove CD player (if equipped). Remove screws attaching console extension to instrument panel, and slide console rearward to remove.
5. Remove Data Link Connector (DLC) and driver's side knee bolster. Lower glove box and remove straps. Remove upper and lower bolts attaching passenger's side lower trim panel to instrument panel. Disconnect electrical connectors and remove panel. Disconnect Yellow connector, remove retaining bolts, and remove passenger's side air bag module. Remove driver's side knee bolster deflector below steering column.
6. Disconnect transmission control cable and electrical connectors from steering column. Remove Body Control Module (BCM) and bracket. Remove driver's side Yellow air bag connector. Remove bolt attaching upper column shaft to lower column shaft in engine compartment. Remove nuts and bolts attaching steering column to upper and lower support brackets. Remove steering column from vehicle.
7. Remove headlight/accessory switch from driver's side of instrument panel. Remove instrument cluster assembly. Remove instrument panel upper brackets and disconnect wiring harness from right upper bracket. (Scheme 16) If equipped with remote keyless entry, disconnect remote function actuator. Disconnect right side bussed electrical center, right side courtesy light, and remove instrument cluster lead from instrument panel.
8. Disconnect parking brake release handle from instrument panel. Remove bolts and nuts from instrument panel, and remove instrument panel from instrument panel carrier support. Remove cross-car duct assembly.
9. Disconnect active transfer case module (if equipped). Disconnect left side bussed electrical center, left side courtesy light, and mid bussed electrical center from bracket. The mid bussed electrical center is located near left kick panel. Remove underhood bussed electrical center and disconnect electrical connectors. Disconnect cruise control and underhood light connectors.
10. Remove windshield wiper arms. Remove air inlet grille outboard sections. Remove air inlet grille at base of windshield. Disconnect wiper module electrical connector. Feed engine compartment harness through bulkhead to inside of vehicle. Remove driver's seat. Disconnect air bag module connector from under seat and remove harness from sill area.
11. Remove carrier side bolts, center support bracket bolt, and remove instrument panel carrier from vehicle. Remove instrument panel carrier from vehicle as one unit, with all parts connected. To install, reverse removal procedure. Tighten fasteners to specification. See «TORQUE SPECIFICATIONS»(/gmc/savana/i-1996-2002/remont/heater/#heater-system__torque-specifications).

Scheme 15

Scheme 16

1. Disable air bag system. See AIR BAG SYSTEM SAFETY article in GENERAL SERVICING. Disconnect negative battery cable. Drain engine coolant. Remove heater hoses at core and plug core openings.
2. Remove right underdash hush panel. Remove screws for instrument panel glove box door, glove box, and bezel. Disconnect electrical connector for glove box light and switch assembly. Remove door, glove box, and bezel from instrument panel. Remove lower right instrument panel mounting bolt.
3. Remove center underdash hush panel. Remove left and right speaker grilles and speakers. Gently pry off defrost grille located on top of instrument panel.
4. Remove left underdash hush panel. Remove 4 screws attaching knee bolster below steering column. Set parking brake. Disconnect emergency brake release cable from ratchet mechanism. Move tilt steering column down (if equipped). Turn ignition key to ON position and move automatic transmission gear selector to low (if equipped). Remove instrument panel accessory trim plate. (Scheme 17) Remove instrument cluster.
5. Remove connectors from Body Control Module (BCM). BCM is located on heater case, in center of dash. Bend snap retainers away from BCM bracket to remove. (Scheme 18) Disconnect connectors on back of A/C-heater control panel and radio. Remove A/C-heater control panel and radio. See «CONTROL PANEL»(/gmc/savana/i-1996-2002/remont/heater/#heater-system).
6. Remove 4 steering column retaining bolts and lower steering column. Remove instrument panel support screws and bolts. Roll instrument panel toward rear of vehicle. Disconnect necessary electrical connectors. Remove instrument panel. (Scheme 17) To install, reverse removal procedure.

Scheme 17

Scheme 18

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

Scheme 19

See also:
• BLOWER CONTROLS SYSTEM CHECK
• SIERRA & SILVERADO
• BLOWER MOTOR
• BLOWER MOTOR
• BLOWER MOTOR
• BLOWER MOTOR
• BLOWER MOTOR
• AUXILIARY BLOWER MOTOR
• TORQUE SPECIFICATIONS