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HVAC System GMC Savana I

Manual HVAC System 17 illustrations ~16059 words

SPECIFICATIONS

ApplicationSpecification
Compressor TypeHarrison HT6 6-Cyl.
Compressor Belt Tension(1)
System Oil Capacity (2)
With Auxiliary System11 ozs.
Without Auxiliary System8 ozs.
Refrigerant (R-134a) Capacity
With Auxiliary System78 ozs.
Without Auxiliary System48 ozs.
System Operating Pressures (3)
High Side251 psi (17.6 kg/cm 2 )
Low Side39 psi (2.7 kg/cm 2 )
(1) Belt tension is adjusted automatically by a spring-tensioned idler pulley. Belt adjustment is not required. (2) Use Polyalkylene Glycol (PAG) oil. (3) Specification is with ambient temperature at 80°F (27°C), relative humidity at 80 percent and engine speed at 1500 RPM.
(1)Belt tension is adjusted automatically by a spring-tensioned idler pulley. Belt adjustment is not required.
(2)Use Polyalkylene Glycol (PAG) oil.
(3)Specification is with ambient temperature at 80°F (27°C), relative humidity at 80 percent and engine speed at 1500 RPM.

SPECIFICATIONS

DESCRIPTION

WARNINGTo avoid injury from accidental air bag deployment, read and carefully follow all SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM procedures in AIR BAG SYSTEM SAFETY article in GENERAL SERVICING.

Heater, Ventilation and Air Conditioning (HVAC) system is a Cycling Clutch Orifice Tube (CCOT) type, designed to cycle compressor on and off to maintain selected temperature, and prevent evaporator icing. Compressor clutch operation is controlled by pressure cycling switch (low pressure cut-off switch) and high pressure cut-off switch. Compressor is equipped with a pressure relief valve to protect refrigerant system from excessive pressure. If discharge pressure exceeds 460-600 psi (32.3-42.2 kg/cm 2 ), valve will open, venting refrigerant to prevent system damage.

Three HVAC systems are available for this vehicle. Front HVAC system, front HVAC system with auxiliary heater, and front HVAC system with auxiliary HVAC system.

Main A/C-heater control module contains 3 control knobs. (Scheme 1) Blower control knob receives power through HTR and A/C fuses. Temperature control knob controls temperature door electronically. Mode knob operates a rotary vacuum switch to control vacuum actuators located in A/C-heater control module.

Auxiliary HVAC assembly is located in left rear of vehicle. Functions of the assembly consist of blower speed, temperature control, and upper or lower mode vent outlets.

The auxiliary A/C (if equipped) operates in conjunction with main HVAC system. Liquid refrigerant flows through auxiliary evaporator at all times when main control is energized. Until auxiliary A/C-heater control module is set to cold, the cold air inside auxiliary HVAC assembly evaporator case is blocked off. A/C control through auxiliary HVAC module controls is unavailable. Only when main A/C control module is on does auxiliary HVAC assembly evaporator receive cooling. (Scheme 2)

The auxiliary heater unit operates independently from main HVAC system. The auxiliary blower motor switches are independent of main system control. Rear blower motor may be operated even when main system is off. A/C operation will not be available and only recirculation of rear air is available.

Scheme 1

Scheme 1
Scheme 1

Scheme 2

Scheme 2
Scheme 2

Temperature Control

Air temperature valve is controlled by temperature valve actuator motor. Actuator motor is controlled by a variable voltage signal from A/C-heater control module temperature control knob. Temperature control knob also contains a vacuum valve that opens and closes vacuum by-pass valve depending on switch position. When temperature control knob is turned left, to coldest position, by-pass valve is closed. Hot water by-pass valve controls engine coolant flow to heater core. (Scheme 3) When temperature control knob is turned slightly clockwise, in hot direction, water valve is opened and heated engine coolant flows through heater core.

Scheme 3

Scheme 3: Temperature Control
Scheme 3: Temperature Control

Mode Controls

Front air delivery or ventilation is controlled by vacuum. Air delivery valves or doors are operated by 4 vacuum actuators. Each actuator is spring loaded for a normal position and will change position when a vacuum is applied. When vacuum is removed, actuator returns to normal position.

Blower Speed Control Knob

Blower speed control knob operates a 4-speed blower motor. (Scheme 1) Blower motor operates with control knob in any position. Blower motor does not operate when mode selector knob is in OFF position.

Mode Selector Knob

Mode selector knob controls a vacuum-operated rotary selector valve. Mode selector routes engine vacuum to operate air door actuators, providing desired air distribution. It also allows for selection of air conditioning or heating functions, including defrost air distribution. Mode selector knob positions are OFF, MAX A/C, bi-level A/C, vent, heater, blend, and DEF (defrost). (Scheme 1)

Temperature Control Knob

Temperature control knob regulates temperature of air entering passenger compartment through electrically operated blend-air door. When knob is in COLD position, air by-passes heater core to provide maximum cooling. (Scheme 1) When knob is in intermediate positions, cooled air from evaporator core and heated air from heater core are mixed to provide desired temperature. When knob is in HOT position, A/C system should be off to provide maximum heating.

Front Auxiliary A/C-Heater Control Module (Passenger Van)

Front auxiliary A/C-heater control module is located overhead, in center of headliner, above rear view mirror. (Scheme 4) The front auxiliary HVAC control module controls auxiliary blower motor at one of 3-speeds, OFF, REAR CNTL, as well as upper vent, lower vent, and temperature positions. When any position other than REAR CNTL is selected, control of rear auxiliary HVAC assembly is from front auxiliary A/C-heater control module. When main system is off or not in A/C mode, auxiliary blower switch can operate blower motor to circulate air in rear passenger compartment.

Scheme 4

Scheme 4: Front Auxiliary A/C-Heater Control Module (Passenger Van)
Scheme 4: Front Auxiliary A/C-Heater Control Module (Passenger Van)

Front Auxiliary A/C-Heater Control Module (Cargo Van)

Front auxiliary A/C-heater control module is located overhead, in center of headliner, above rear view mirror. (Scheme 5) Functions of the front A/C-heater control module operate in the same manner as the passenger van, with the exception of no REAR CNTL function.

Rear Auxiliary A/C-Heater Control Module

Rear auxiliary A/C-heater control module is located overhead, behind front seats. When front auxiliary HVAC control is set to REAR CNTL, rear auxiliary A/C-heater control module regulates temperature, auxiliary blower motor speeds, and mode operation the same as front control with the exception of REAR CNTL mode. (Scheme 5)

Scheme 5

Scheme 5: Rear Auxiliary A/C-Heater Control Module
Scheme 5: Rear Auxiliary A/C-Heater Control Module

HIGH PRESSURE CUT-OFF SWITCH

The high pressure cut-off switch, located on rear of compressor, is designed to interrupt compressor operation in the event of excessively high operating pressure. Switch is normally closed and will open if pressure exceeds 410-450 psi (28.8-31.6 kg/cm 2 ).

PRESSURE CYCLING SWITCH

Note. Pressure cycling switch may also be referred as low pressure cut-off switch.

Switch is mounted on low-side Schrader valve type fitting and controls compressor operation. If low-side pressure decreases to approximately 23 psi (1.6 kg/cm 2 ), switch opens, interrupting power to compressor clutch. When pressure increases to about 46 psi (3.2 kg/cm 2 ), switch closes, providing power to compressor clutch. Switch maintains evaporator surface at a temperature slightly warmer than freezing, to prevent evaporator icing and airflow blockage during normal system operation.

HIGH PRESSURE RELIEF VALVE

High pressure relief valve, located near compressor, protects refrigerant system from excessively high pressure. If high-side pressure exceeds 410-460 psi (28-31 kg/cm 2 ), valve opens, venting refrigerant to prevent system damage.

TROUBLE SHOOTING

WARNINGTo avoid injury from accidental air bag deployment, read and carefully follow all SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM procedures in AIR BAG SYSTEM SAFETY article in GENERAL SERVICING.

Note. Before performing trouble shooting procedures, ensure appropriate HVAC fuses and blower motor relays (if equipped) are okay. Ensure ground connections are clean and tight.

Note. For additional trouble shooting information, see MANUAL A/C-HEATER SYSTEMS -TROUBLE SHOOTING article.

BLOWER CONTROLS SYSTEM CHECK

See HEATER SYSTEMS - RWD TRUCKS & VANS - EXCEPT TRACKER article.

Blower Motor Inoperative

See HEATER SYSTEMS - RWD TRUCKS & VANS - EXCEPT TRACKER article.

Blower Motor Inoperative At High Speed

See HEATER SYSTEMS - RWD TRUCKS & VANS - EXCEPT TRACKER article.

Blower Motor Operates At High Speed Only

See HEATER SYSTEMS - RWD TRUCKS & VANS - EXCEPT TRACKER article.

Blower Motor Inoperative At Medium-High (M2) Position

See HEATER SYSTEMS - RWD TRUCKS & VANS - EXCEPT TRACKER article.

Blower Motor Inoperative At Medium-Low (M1) Position

See HEATER SYSTEMS - RWD TRUCKS & VANS - EXCEPT TRACKER article.

Blower Motor Inoperative At Low Speed

See HEATER SYSTEMS - RWD TRUCKS & VANS - EXCEPT TRACKER article.

Blower Motor Operates Continuously

See HEATER SYSTEMS - RWD TRUCKS & VANS - EXCEPT TRACKER article.

Auxiliary Blower Motor Does Not Operate At High Speed

  1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check). Go to next step.
  2. Disconnect auxiliary blower motor high-speed relay connector. (Scheme 2) Connect test light between ground and terminal C1 (Red wire) of high-speed relay connector. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). If test light comes on, go to next step. If test light does not come on, go to step 13.
  3. Turn ignition switch to ON position. Connect test light between ground and terminal C2 (Brown wire) of high-speed relay connector. If test light comes on, go to next step. If test light does not come on, go to step 14.
  4. Disconnect auxiliary blower motor connector. Use a DVOM to check for continuity between auxiliary blower motor high-speed relay connector terminal A2 (Yellow wire) 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 15.
  5. If vehicle is equipped with a rear A/C-heater control module, go to step 8. If vehicle is not equipped with a rear A/C-heater control module, go to next step.
  6. Place front auxiliary A/C-heater control module blower switch in HI position. Use a DVOM to check for continuity between ground and high-speed relay connector terminal A1 (White wire). If continuity is indicated, go to step 16. If continuity is not indicated, go to next step.
  7. Disconnect front auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between front auxiliary A/C-heater control module pins "D" and "F". If continuity is indicated, go to step 17. If continuity is not indicated, go to step 19.
  8. If auxiliary blower motor operates from rear A/C-heater control module, go to next step. If auxiliary blower motor does not operate from rear A/C-heater control module, go to step 11.
  9. Place front auxiliary A/C-heater control module blower switch in HI position. Use a DVOM to check for continuity between ground and high-speed relay connector terminal A1 (White wire). If continuity is indicated, go to step 16. If continuity is not indicated, go to next step.
  10. Disconnect front auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between front auxiliary A/C-heater control module pins "B" and "D". If continuity is indicated, go to step 18. If continuity is not indicated, go to step 19.
  11. Place front auxiliary A/C-heater control module in REAR CNTL position. Place rear auxiliary A/C-heater control module in HI position. Use a DVOM to check for continuity between auxiliary blower motor high relay connector terminal A1 (White wire) and ground. If continuity is indicated, go to step 16. If continuity is not indicated, go to next step.
  12. Disconnect rear auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between rear auxiliary A/C-heater control module pins "B" and "D". If continuity is indicated, go to step 20. If continuity is not indicated, go to step 21.
  13. Repair open in Red wire between high-speed relay connector and splice S412. Splice S412 is located in rear A/C harness, approximately 9" (13 cm) from auxiliary blower motor relay breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  14. Repair open in Brown wire between high-speed relay connector and splice S405. Splice S405 is located in rear A/C harness approximately 2.8" (7 cm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  15. Repair open in Yellow wire between high-speed relay connector and splice S413. Splice S413 is located in rear A/C harness, approximately 5.9" (15 cm) from blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  16. Replace auxiliary blower motor high-speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  17. Repair open circuit between auxiliary blower motor high-speed relay connector and rear auxiliary A/C-heater control module connector (Orange wire becomes White wire at high-speed relay connector). Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  18. Repair open in Orange wire between front auxiliary A/C-heater control module connector and splice S321. Splice S321 is located in rear A/C harness, approximately 5" (13 cm) from rear auxiliary A/C-heater control module breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  19. Replace front auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  20. Repair open in Orange wire between rear auxiliary A/C-heater control module connector and splice S321. Splice S321 is located in rear A/C harness, approximately 5" (13 cm) from rear auxiliary A/C-heater control module breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  21. Replace rear auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).

Auxiliary Blower Motor Does Not Operate At Medium Speed

  1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check). Go to next step.
  2. Disconnect auxiliary blower motor medium-speed relay connector. (Scheme 2) Connect test light between ground and terminal C1 (Red wire) of medium-speed relay connector. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). If test light comes on, go to next step. If test light does not come on, go to step 13.
  3. Turn ignition switch to ON position. Connect a test light between ground and terminal C2 (Brown wire) of medium-speed relay connector. If test light comes on, go to next step. If test light does not come on, go to step 14.
  4. Disconnect auxiliary blower motor connector. Use a DVOM to check for continuity between auxiliary blower motor medium-speed relay connector terminal A2 (Yellow wire) 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 15.
  5. If vehicle is equipped with a rear A/C-heater control module, go to step 8. If vehicle is not equipped with a rear A/C-heater control module, go to next step.
  6. Place front auxiliary A/C-heater control module blower switch in medium position. Use a DVOM to check for continuity between ground and medium-speed relay connector terminal A1 (Red wire). If continuity is indicated, go to step 16. If continuity is not indicated, go to next step.
  7. Disconnect front auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between front auxiliary A/C-heater control module pins "E" and "F". If continuity is indicated, go to step 17. If continuity is not indicated, go to step 19.
  8. If auxiliary blower motor operates from rear A/C-heater control module, go to next step. If auxiliary blower motor does not operate from rear A/C-heater control module, go to step 11.
  9. Place front auxiliary A/C-heater control module blower switch in medium position. Use a DVOM to check for continuity between ground and medium-speed relay connector terminal A1 (Red wire). If continuity is indicated, go to step 16. If continuity is not indicated, go to next step.
  10. Disconnect front auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between front auxiliary A/C-heater control module pins "B" and "E". If continuity is indicated, go to step 18. If continuity is not indicated, go to step 19.
  11. Place front auxiliary A/C-heater control module in REAR CNTL position. Place rear auxiliary A/C-heater control module in medium position. Use a DVOM to check for continuity between auxiliary blower motor medium-speed relay connector terminal A1 (Red wire) and ground. If continuity is indicated, go to step 16. If continuity is not indicated, go to next step.
  12. Disconnect rear auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between rear auxiliary A/C-heater control module pins "B" and "E". If continuity is indicated, go to step 20. If continuity is not indicated, go to step 21.
  13. Repair open in Red wire between medium-speed relay connector and splice S412. S412 is located in the rear A/C harness approximately 9" (13 cm) from auxiliary blower motor relay breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  14. Repair open in Brown wire between medium-speed relay connector and splice S405. Splice S405 is located in rear A/C harness, approximately 2.8" (7 cm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  15. Repair open in Yellow wire between medium-speed relay connector and splice S413. Splice S413 is located in rear A/C harness, approximately 5.9" (15 cm) from blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  16. Replace auxiliary blower motor medium-speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  17. Repair open circuit between auxiliary blower motor medium-speed relay connector and front auxiliary A/C-heater control module connector (Red wire becomes Tan wire at medium-speed relay connector). Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  18. Repair open in Tan wire between front auxiliary A/C-heater control module connector and splice S321. Splice S321 is located in rear A/C harness, approximately 5" (13 cm) from rear auxiliary A/C-heater control module breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  19. Replace front auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  20. Repair open in Tan wire between rear auxiliary A/C-heater control module connector and splice S321. Splice S321 is located in rear A/C harness, approximately 5" (13 cm) from rear auxiliary A/C-heater control module breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  21. Replace rear auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).

Auxiliary Blower Motor Does Not Operate At Low Speed

  1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check). Go to next step.
  2. Disconnect auxiliary blower motor low-speed relay connector. (Scheme 2) Connect a test light between ground and terminal C1 (Red wire) of low-speed relay connector. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). If test light comes on, go to next step. If test light does not come on, go to step 13.
  3. Turn ignition switch to ON position. Connect a test light between ground and terminal C2 (Brown wire) of low-speed relay connector. If test light comes on, go to next step. If test light does not come on, go to step 14.
  4. Disconnect auxiliary blower motor connector. Use a DVOM to check for continuity between auxiliary blower motor low-speed relay connector terminal A2 (Yellow wire) 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 15.
  5. If vehicle is equipped with a rear A/C-heater control module, go to step 8. If vehicle is not equipped with a rear A/C-heater control module, go to next step.
  6. Place front auxiliary A/C-heater control module blower switch in low position. Use a DVOM to check for continuity between ground and low-speed relay connector terminal A1 (Dark Blue wire). If continuity is indicated, go to step 16. If continuity is not indicated, go to next step.
  7. Disconnect front auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between front auxiliary A/C-heater control module pins "C" and "F". If continuity is indicated, go to step 17. If continuity is not indicated, go to step 19.
  8. If auxiliary blower motor operates from rear A/C-heater control module, go to next step. If auxiliary blower motor does not operate from rear A/C-heater control module, go to step 11.
  9. Place front auxiliary A/C-heater control module blower switch in low position. Use a DVOM to check for continuity between ground and low-speed relay connector terminal A1 (Dark Blue wire). If continuity is indicated, go to step 16. If continuity is not indicated, go to next step.
  10. Disconnect front auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between front auxiliary A/C-heater control module pins "B" and "C". If continuity is indicated, go to step 18. If continuity is not indicated, go to step 19.
  11. Place front auxiliary A/C-heater control module in REAR CNTL position. Place rear auxiliary A/C-heater control module in low position. Use a DVOM to check for continuity between auxiliary blower motor low-speed relay connector terminal A1 (Dark Blue wire) and ground. If continuity is indicated, go to step 16. If continuity is not indicated, go to next step.
  12. Disconnect rear auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between rear auxiliary A/C-heater control module pins "B" and "C". If continuity is indicated, go to step 20. If continuity is not indicated, go to step 21.
  13. Repair open in Red wire between low-speed relay connector and splice S412. Splice S412 is located in rear A/C harness, approximately 9" (13 cm) from auxiliary blower motor relay breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  14. Repair open in Brown wire between low-speed relay connector and splice S405. Splice S405 is located in rear A/C harness, approximately 2.8" (7 cm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  15. Repair open in Yellow wire between low-speed relay connector and splice S413. Splice S413 is located in rear A/C harness, approximately 5.9" (15 cm) from blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  16. Replace auxiliary blower motor low-speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  17. Repair open circuit between auxiliary blower motor low-speed relay connector and front auxiliary A/C-heater control module connector (Dark Blue wire becomes Yellow wire at low-speed relay connector). Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  18. Repair open in Yellow wire between front auxiliary A/C-heater control module connector and splice S321. Splice S321 is located in rear A/C harness, approximately 5" (13 cm) from rear auxiliary A/C-heater control module breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  19. Replace front auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  20. Repair open in Yellow wire between rear auxiliary A/C-heater control module connector and splice S321. Splice S321 is located in rear A/C harness, approximately 5" (13 cm) from rear auxiliary A/C-heater control module breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  21. Replace rear auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).

Auxiliary Blower Motor Inoperative At High Speed

  1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check). Go to next step.
  2. Disconnect auxiliary blower motor high-speed relay connector. (Scheme 2) Connect a test light between ground and terminal C1 (Red wire) of high-speed relay connector. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). If test light comes on, go to next step. If test light does not come on, go to step 13.
  3. Turn ignition switch to ON position. Connect a test light between ground and terminal C2 (Brown wire) of high-speed relay connector. If test light comes on, go to next step. If test light does not come on, go to step 14.
  4. Disconnect auxiliary blower motor connector. Use a DVOM to check for continuity between auxiliary blower motor high-speed relay connector terminal A2 (Yellow wire) 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 15.
  5. If vehicle is equipped with a rear A/C-heater control module, go to step 8. If vehicle is not equipped with a rear A/C-heater control module, go to next step.
  6. Place front auxiliary A/C-heater control module blower switch in HI position. Use a DVOM to check for continuity between ground and high-speed relay connector terminal A1 (White wire). If continuity is indicated, go to step 16. If continuity is not indicated, go to next step.
  7. Disconnect front auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between front auxiliary A/C-heater control module pins "D" and "F". If continuity is indicated, go to step 17. If continuity is not indicated, go to step 19.
  8. If auxiliary blower motor operates from rear A/C-heater control module, go to next step. If auxiliary blower motor does not operate from rear A/C-heater control module, go to step 11.
  9. Place front auxiliary A/C-heater control module blower switch in HI position. Use a DVOM to check for continuity between ground and high-speed relay connector terminal A1 (White wire). If continuity is indicated, go to step 16. If continuity is not indicated, go to next step.
  10. Disconnect front auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between front auxiliary A/C-heater control module pins "B" and "D". If continuity is indicated, go to step 18. If continuity is not indicated, go to step 19.
  11. Place front auxiliary A/C-heater control module in REAR CNTL position. Place rear auxiliary A/C-heater control module in high position. Use a DVOM to check for continuity between auxiliary blower motor high-speed relay connector terminal A1 (White wire) and ground. If continuity is indicated, go to step 16. If continuity is not indicated, go to next step.
  12. Disconnect rear auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between rear auxiliary A/C-heater control module pins "B" and "D". If continuity is indicated, go to step 20. If continuity is not indicated, go to step 21.
  13. Repair open in Red wire between high-speed relay connector and splice S412. Splice S412 is located in rear A/C harness, approximately 9" (13 cm) from auxiliary blower motor relay breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  14. Repair open in Brown wire between high-speed relay connector and splice S405. Splice S405 is located in rear A/C harness, approximately 2.8" (7 cm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  15. Repair open in Yellow wire between high-speed relay connector and splice S413. Splice S413 is located in rear A/C harness, approximately 5.9" (15 cm) from blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  16. Replace auxiliary blower motor high-speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  17. Repair open circuit between auxiliary blower motor high-speed relay connector and front auxiliary A/C-heater control module connector (White wire becomes Orange wire at high-speed relay connector). Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  18. Repair open in Orange wire between front auxiliary A/C-heater control module connector and splice S321. Splice S321 is located in rear A/C harness, approximately 5" (13 cm) from rear auxiliary A/C-heater control module breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  19. Replace front auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  20. Repair open in Orange wire between rear auxiliary A/C-heater control module connector and splice S321. Splice S321 is located in rear A/C harness, approximately 5" (13 cm) from rear auxiliary A/C-heater control module breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  21. Replace rear auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).

Auxiliary Blower Motor Operates At High Speed Only

  1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check). Go to next step.
  2. Disconnect auxiliary blower motor resistor connector. Disconnect auxiliary blower motor connector. (Scheme 2) Use a DVOM to check 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/manual-hvac-system/#hvac-system). If continuity is indicated, go to next step. If continuity is not indicated, go to step 4.
  3. Replace auxiliary blower motor resistor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  4. Repair open in Yellow wire between auxiliary blower motor resistor and splice S413. Splice S413 is located in rear A/C harness, approximately 5.9" (15 cm) from blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).

Auxiliary Blower Motor Inoperative

  1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check). Go to next step.
  2. Disconnect auxiliary blower motor low-speed relay connector. (Scheme 2) Connect test light between ground and auxiliary blower motor low-speed relay cavity terminal C1 (Red wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-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 test light between ground and terminal C2 (Brown wire) of low-speed relay connector. If test light comes on, go to next step. If test light does not come on, go to step 9.
  4. Disconnect front auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between ground and terminal "F" (Black wire) of front auxiliary A/C-heater control module connector. If continuity is indicated, go to next step. If continuity is not indicated, go to step 10.
  5. Place front auxiliary A/C-heater control module blower switch to LO position. Use a DVOM to check for continuity between front auxiliary HVAC module pins "C" and "F". 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 ground and terminal "A" (Black wire) of auxiliary blower motor connector. 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 resistor connector terminal "D" (Yellow wire) 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 in rear A/C harness, approximately 9" (13 cm) from auxiliary blower motor relay breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  9. Repair open in Brown wire between instrument panel fuse block and splice S405. Splice S405 is located in rear A/C harness, approximately 2.8" (7 cm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  10. Repair open in Black wire between rear auxiliary A/C-heater control module connector and ground G400. Ground G400 is located near rear wheelwell. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  11. Replace front auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  12. Repair open in Black wire between auxiliary blower motor connector and ground G400. Ground G400 is located near rear wheelwell. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  13. Replace auxiliary blower motor. See «BLOWER MOTORS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__removal-installation-auxiliary-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  14. Repair open in Yellow wire between auxiliary blower motor connector and splice S413. Splice S413 is located in rear A/C harness, approximately 5.9" (15 cm) from blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).

Auxiliary Blower Motor Always On

  1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check). Go to next step.
  2. Place front auxiliary A/C-heater control module blower switch in OFF position. Disconnect connectors from auxiliary blower motor, auxiliary blower motor resistor and 3 auxiliary blower motor relays. (Scheme 2) Turn ignition switch to ON position. Connect test light between ground and auxiliary blower motor connector terminal "B" (Yellow wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). If test light comes on, go to step 13. If test light does not come on, go to next step.
  3. Connect test light between ground and auxiliary blower motor resistor connector terminal "A" (Yellow wire). If test light comes on, go to step 14. If test light does not come on, go to next step.
  4. Connect test light between ground and auxiliary blower motor resistor connector terminal "C" (Light Blue wire). If test light comes on, go to step 15. If test light does not come on, go to next step.
  5. Reattach connectors to auxiliary blower motor resistor, auxiliary blower motor and auxiliary blower motor low-speed relay. If auxiliary blower motor comes on, go to next step. If auxiliary blower motor does not come on, go to step 8.
  6. Disconnect front auxiliary A/C-heater control module. If auxiliary blower motor turns off, go to step 16. If auxiliary blower motor does not turn off, go to next step.
  7. Disconnect auxiliary blower motor low-speed relay connector. Connect self-powered test light between ground and low-speed relay connector terminal A1 (Dark Blue wire). If test light comes on, go to step 17. If test light does not come on, go to step 18.
  8. Reconnect auxiliary blower motor medium-speed relay connector. If auxiliary blower motor comes on, go to next step. If auxiliary blower motor does not come on, go to step 11.
  9. Disconnect front auxiliary A/C-heater control module connector. If auxiliary blower motor turns off, go to step 16. If auxiliary blower motor does not turn off, go to next step.
  10. Disconnect auxiliary blower motor medium-speed relay connector. Use a DVOM to check continuity between ground and auxiliary blower motor medium-speed relay connector terminal A1 (Red wire). If continuity is indicated, go to step 19. If continuity is not indicated, go to step 20.
  11. Disconnect front auxiliary A/C-heater control module connector. Use a DVOM to check continuity between front auxiliary A/C-heater control module connector terminals "D" (Orange wire) and "F" (Black wire). If continuity is indicated, go to step 21. If continuity is not indicated, go to next step.
  12. With front auxiliary A/C-heater control module disconnected, use a DVOM to check continuity between front auxiliary A/C-heater control module terminals "D" and "F". If continuity is indicated, go to step 16. If continuity is not indicated, go to step 22.
  13. Repair short to voltage in Yellow wire between auxiliary blower motor resistor, high-speed relay and blower motor. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  14. Repair short to voltage in Yellow wire between auxiliary blower motor resistor and low-speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  15. Repair short to voltage in Light Blue wire between auxiliary blower motor resistor and medium-speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  16. Replace front auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  17. Repair short to ground in Dark Blue or Yellow wire between low-speed relay connector and front auxiliary A/C-heater control module. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  18. Replace auxiliary blower motor low-speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  19. Repair short to ground in Red or Tan wire between medium-speed relay connector and front auxiliary A/C-heater control module. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  20. Replace auxiliary blower motor medium-speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  21. Repair short to ground in White or Orange wire between front auxiliary A/C-heater control module connector and auxiliary blower motor high-speed relay connector. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  22. Replace auxiliary blower motor high-speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check). Go to next step.
  2. Disconnect auxiliary blower motor low-speed relay connector. (Scheme 2) Connect test light between ground and terminal C1 (Red wire) of connector. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). If test light comes on, go to next step. If test light does not come on, go to step 13.
  3. Turn ignition switch to ON position. Connect a test light between ground and terminal C2 (Brown wire) of low-speed relay connector. If test light comes on, go to next step. If test light does not come on, go to step 14.
  4. Disconnect front auxiliary A/C-heater control module connector. Connect self-powered test light between ground and terminal "B" (Black wire) of front auxiliary A/C-heater control module connector. If test light comes on, go to next step. If test light does not come on, go to step 15.
  5. If auxiliary motor can be controlled from rear auxiliary A/C-heater control module, go to next step. If auxiliary motor cannot be controlled from rear auxiliary A/C-heater control module, go to step 9.
  6. Place front auxiliary A/C-heater control module blower switch in LOW position. Use a DVOM to check for continuity between front auxiliary A/C-heater control module pins "C" and "B". If continuity is indicated, go to next step. If continuity is not indicated, go to step 16.
  7. Disconnect auxiliary blower motor connector. Use a DVOM to check for continuity between ground and terminal "A" (Black wire) of auxiliary blower motor connector. If continuity is indicated, go to next step. If continuity is not indicated, go to step 17.
  8. Disconnect auxiliary blower motor resistor connector. Use a DVOM to check for continuity between resistor connector terminal "D" and blower motor connector terminal "B" (Yellow wire). If continuity is indicated, go to step 18. If continuity is not indicated, go to step 19.
  9. Place front auxiliary A/C-heater control module in REAR CNTL position. Use a DVOM to check for continuity between front auxiliary A/C-heater control module pins "B" and "F". If continuity is indicated, go to next step. If continuity is not indicated, go to step 16.
  10. Disconnect auxiliary HVAC logic module, located behind front auxiliary A/C-heater control module. Use a DVOM to check for continuity between auxiliary HVAC logic module connector terminal "M" and front auxiliary A/C-heater control module connector terminal "F" (Light Blue wire). If continuity is indicated, go to next step. If continuity is not indicated, go to step 20.
  11. Connect DVOM between auxiliary HVAC logic module pins "M" and "L". Set DVOM to diode testing mode. Observe DVOM readings. Reverse terminals of DVOM on auxiliary HVAC logic module pins. Observe DVOM readings. If diode tests okay, go to next step. If diode does not test okay, go to step 21.
  12. Disconnect rear auxiliary A/C-heater control module. Place rear auxiliary A/C-heater control module in LO position. Use a DVOM to check for continuity between rear auxiliary A/C-heater control module pins "C" and "F". If continuity is indicated, go to step 22. If continuity is not indicated, go to step 23.
  13. Repair open in Red wire between underhood fuse/relay center and splice S412. Splice S412 is located in rear A/C harness, approximately 9" (13 cm) from auxiliary blower motor relay breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  14. Repair open in Brown wire between instrument panel fuse block and splice S405. Splice S405 is located in rear A/C harness, approximately 2.8" (7 cm) from auxiliary blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  15. Repair open in Black wire between front auxiliary HVAC control connector and ground G400. Ground G400 is located near rear wheelwell. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  16. Replace front auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  17. Repair open in Black wire between auxiliary blower motor connector and ground G400. Ground G400 is located near rear wheelwell. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  18. Replace auxiliary blower motor. See «BLOWER MOTORS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__removal-installation-auxiliary-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  19. Repair open in Yellow wire between auxiliary blower motor connector and splice S413. Splice S413 is located in rear A/C harness, approximately 5.9" (15 cm) from blower motor resistor breakout. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  20. Repair open in Light Blue wire between auxiliary HVAC logic module and front auxiliary A/C-heater control module. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  21. Replace auxiliary A/C-heater control logic module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  22. Repair open in Dark Blue wire between auxiliary HVAC logic module and rear auxiliary A/C-heater control module. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  23. Replace rear auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  1. Perform «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check). Go to next step.
  2. Place front and rear auxiliary A/C-heater control module blower switches to OFF position. Disconnect connectors from auxiliary blower motor, auxiliary blower motor resistor and 3 auxiliary blower motor relays. (Scheme 2) Turn ignition switch to ON position. Connect a test light between ground and auxiliary blower motor connector terminal "B" (Yellow wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). If test light comes on, go to step 15). If test light does not come on, go to next step.
  3. Connect a test light between ground and auxiliary blower motor resistor connector terminal "A" (Yellow wire). If test light comes on, go to step 16). If test light does not come on, go to next step.
  4. Connect a test light between ground and auxiliary blower motor resistor connector terminal "C" (Light Blue wire). If test light comes on, go to step 17). If test light does not come on, go to next step.
  5. Reconnect auxiliary blower motor, blower motor resistor and 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 9.
  6. Disconnect front auxiliary A/C-heater control module connector. If auxiliary blower motor stops running, go to step 18). If auxiliary blower motor does not stop running, go to next step.
  7. Disconnect rear auxiliary A/C-heater control module connector. If auxiliary blower motor stops running, go to step 19). If auxiliary blower motor does not stop running, go to next step.
  8. Disconnect auxiliary blower motor low-speed relay. Use a DVOM to check for continuity between ground and low-speed relay connector terminal A1 (Dark Blue wire). If continuity is indicated, go to step 20). If continuity is not indicated, go to step 21).
  9. 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 13).
  10. Disconnect front auxiliary A/C-heater control module connector. If auxiliary blower motor stops running, go to step 18). If auxiliary blower motor does not stop running, go to next step.
  11. Disconnect rear auxiliary A/C-heater control module connector. If auxiliary blower motor stops running, go to step 19). If auxiliary blower motor does not stop running, go to next step.
  12. Disconnect auxiliary blower motor medium-speed relay. Use a DVOM to check for continuity between ground and medium-speed relay connector terminal A1 (Red wire). If continuity is indicated, go to step 20). If continuity is not indicated, go to step 21).
  13. Disconnect front auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between front auxiliary A/C-heater control module connector terminals "D" (Orange wire) and "B" (Black wire). If continuity is indicated, go to next step. If continuity is not indicated, go to step 18).
  14. Disconnect rear auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between rear auxiliary A/C-heater control module connector terminals "D" (Orange wire) and "B" (Black wire). If continuity is indicated, go to step 24). If continuity is not indicated, go to step 25).
  15. Repair short to 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/manual-hvac-system/#hvac-system__blower-controls-system-check).
  16. Repair short to voltage in Yellow wire between auxiliary blower motor resistor and auxiliary blower motor low-speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  17. Repair short to voltage in Light Blue wire between auxiliary blower motor resistor and auxiliary blower motor medium-speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  18. Replace front auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  19. Replace rear auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  20. Repair short to ground in Dark Blue wire/Yellow wire between auxiliary blower motor low-speed relay (Dark Blue wire) and front or rear auxiliary A/C-heater control modules (Yellow wire). Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  21. Replace auxiliary blower motor low-speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  22. Repair short to ground in Red wire/Tan wire between auxiliary blower motor medium-speed relay (Red wire) and front or rear auxiliary A/C-heater control modules (Tan wire). Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  23. Replace auxiliary blower motor medium-speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  24. Repair short to ground in White wire/Orange wire between auxiliary blower motor high-speed relay (White wire) and front or rear auxiliary A/C-heater control modules (Orange wire). Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).
  25. Replace auxiliary blower motor high-speed relay. Go to «BLOWER CONTROLS SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__blower-controls-system-check).

A/C COMPRESSOR CLUTCH

Note. Pressure cycling switch may also be referred to as a low pressure cut-off switch.

Preliminary Inspection

Ensure ambient temperature is greater than 50°F (10°C). Ensure A/C compressor drive belt is properly installed and in good condition. Ensure A/C compressor rotates freely and is not obstructed. Eliminate any condition that sets Diagnostic Trouble Codes (DTCs) that could impact vehicle or A/C compressor operation.

A/C Compressor Clutch Does Not Engage

  1. Perform HVAC compressor controls system check. See A/C COMPRESSOR CLUTCH CONTROLS - ALL MODELS article. Go to next step.
  2. Use a DVOM to check condition of diode D102. Diode D102 is located in underhood fuse/relay center, at left front of engine compartment. If diode tests okay, go to next step. If diode does not test okay, go to step 39) .
  3. Check A/C-heater related fuses in instrument panel fuse block and underhood fuse/relay center. Replace as necessary. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) . Check that A/C compressor clutch operates freely and drive belt is secure. Check A/C compressor relay for poor connection. Check compressor circuit grounds. Start engine and operate at 1000 RPM. Place blower switch on main A/C-heater control module in HI position. Ensure blower motor comes on. Rotate mode selector knob on main A/C-heater control module (heater and A/C control module) to MAX A/C position. Set temperature control in full cold setting. Cold air should be produced. If A/C compressor clutch engages within 5 minutes, see MANUAL A/C-HEATER SYSTEMS - TROUBLE SHOOTING article. If A/C compressor clutch does not engage, go to next step.
  4. Turn ignition switch to OFF position. Place blower switch in OFF position. Turn ignition switch to ON position. Remove A/C compressor clutch relay. Momentarily connect fused jumper wire between relay connector terminals D3 (Pink wire) and D1 (Dark Green wire). Repeat as necessary, and listen for compressor operation. If A/C compressor clutch energizes, go to step 7) . If A/C compressor clutch does not energize, go to next step.
  5. Remove fused jumper wire. Disconnect A/C compressor clutch connector. Use a DVOM to check for continuity between ground and clutch coil connector terminal "A" (Black wire). If continuity is indicated, go to next step. If continuity is not indicated, go to step 22) .
  6. Use a DVOM to check for continuity between A/C compressor clutch connector terminal "B" (Dark Green wire) and A/C compressor clutch relay connector terminal D1 (Dark Green wire). If continuity is indicated, go to step 23) . If continuity is not indicated, go to step 24) .
  7. Connect test light between ground and A/C compressor clutch relay connector terminal D3 (Pink wire). If test light comes on, go to next step. If test light does not come on, go to step 25) .
  8. Connect test light between ground and A/C compressor clutch relay connector terminal C3 (Orange wire). If test light comes on, go to next step. If test light does not come on, go to step 26) .
  9. Disconnect Vehicle Control Module (VCM) connector C3 (gasoline engines) or Powertrain Control Module (PCM) connector C3 (diesel engines). Connect a self-powered test light between A/C compressor clutch relay connector terminal C1 (Dark Green/White wire) and VCM connector C3 terminal No. 1 or PCM connector C3 terminal D5. If test light comes on, go to next step. If test light does not come on, go to step 27) .
  10. Install A/C compressor clutch relay. Connect a fused jumper wire between ground and VCM connector C3 terminal No. 1 (Dark Green/White wire) or PCM connector C3 terminal D5 (Dark Green/White wire). If A/C compressor clutch energizes, go to next step. If A/C compressor clutch does not energize, go to step 28) .
  11. Disconnect high pressure cut-off switch connector. On diesel models, disconnect PCM connector C1. Use a DVOM to check for continuity between high pressure cut-off switch connector terminal "A" (Dark Green/White wire) and VCM connector C3 terminal No. 25 or PCM connector C1 terminal C2. If continuity is indicated, go to next step. If continuity is not indicated, go to step 29) .
  12. Reconnect VCM or PCM connector C3. Reconnect PCM connector C1. Disconnect A/C compressor clutch connector. Connect test light between ground and A/C compressor clutch connector terminal "B" (Dark Green wire). Connect a fused jumper wire between positive battery terminal and high pressure cut-off switch connector terminal "A" (Dark Green/White wire). Ensure jumper wire is clear of fan blades. Start and operate engine at 1000 RPM. If test light comes on, go to next step. If test light does not come on, go to step 30) .
  13. Turn ignition switch to OFF position. Remove fused jumper wire. Use a DVOM to check for continuity between high pressure, cut-off switch pins "A" and "B". If continuity is indicated, go to next step. If continuity is not indicated, go to step 31) .
  14. If vehicle is equipped with a gasoline engine, go to step 17) . If vehicle is equipped with a diesel engine, go to next step.
  15. Disconnect A/C compressor low pressure cut-off switch connector. Use a DVOM to check for continuity between low pressure cut-off switch connector terminal "B" (Dark Green wire) and high pressure cut-off switch connector terminal "B" (Dark Green wire). If continuity is indicated, go to next step. If continuity is not indicated, go to step 32) .
  16. Use a DVOM to check for continuity between low pressure cut-off switch pins "A" and "B". If continuity is indicated, go to step 20) . If continuity is not indicated, go to step 33) .
  17. Disconnect low pressure cut-off switch connector. Use a DVOM to check for continuity between low pressure cut-off switch connector terminal "A" (Black wire) and ground. If continuity is indicated, go to next step. If continuity is not indicated, go to step 34) .
  18. Use a DVOM to check for continuity between low pressure, cut-off switch pins "A" and "B". If continuity is indicated, go to next step. If continuity is not indicated, go to step 33) .
  19. Disconnect Vehicle Control Module (VCM) connector C3 (gasoline engine). Use a DVOM to check for continuity between VCM connector C3 terminal No. 30 and low pressure cut-off switch connector terminal "B" (Dark Green wire). If continuity is indicated, go to next step. If continuity is not indicated, go to step 35) .
  20. Disconnect main A/C-heater control module connector C2. Use a DVOM to check for continuity between main A/C-heater control module connector C2 terminal "H" (Light Green wire) and high pressure cut-off switch terminal "A" (gasoline engine) or low pressure cut-off switch connector terminal "B" (diesel engine). If continuity is indicated, go to next step. If continuity is not indicated, go to step 36) .
  21. Turn ignition switch to ON position. Connect test light between main A/C-heater control module connector C2 terminal "E" (Brown wire) and ground. If test light comes on, go to step 37) . If test light does not come on, go to step 38) .
  22. Repair open in Black wire between A/C compressor clutch and ground. Recheck compressor operation.
  23. Replace A/C compressor. See «COMPRESSOR»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Recheck compressor operation.
  24. Repair open in Dark Green wire between A/C compressor clutch relay and A/C compressor clutch. Recheck compressor operation.
  25. Repair open in Pink wire between IGN-E fuse (10-amp) in underhood fuse/relay center and A/C compressor clutch relay. Recheck compressor operation.
  26. Repair open in Orange wire between A/C fuse (10-amp) in underhood fuse/relay center and A/C compressor clutch relay. Recheck compressor operation.
  27. Repair open in Dark Green/White wire between A/C compressor clutch relay and VCM (gasoline engines) or PCM (diesel engines) connector C3. Recheck compressor operation.
  28. Replace A/C compressor clutch relay. Recheck compressor operation.
  29. Repair open in Dark Green/White wire between high pressure cut-off switch and VCM (gasoline engines) connector C3 or PCM (diesel engines) connector C1. Recheck compressor operation.
  30. Replace VCM (gasoline engines) or PCM (diesel engines). See «PCM/VCM REPLACEMENT»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Recheck compressor operation.
  31. Replace high pressure cut-off switch. See «HIGH PRESSURE CUT-OFF SWITCH»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Recheck compressor operation.
  32. Repair open in Dark Green wire between high and low pressure cut-off switches. Recheck compressor operation.
  33. Replace low pressure cut-off switch. Recheck compressor operation.
  34. Repair open in Black wire between low pressure cut-off switch and ground. Recheck compressor operation.
  35. Repair open in Dark Green wire between VCM connector C3 (gasoline engines) and low pressure cut-off switch. Recheck compressor operation.
  36. Repair open in Light Green wire between A/C-heater control module and pressure switch. Recheck compressor operation.
  37. Replace main A/C-heater control module. See «A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Recheck compressor operation.
  38. Repair open in Brown wire between A/C-heater control module and underhood fuse/relay center. Recheck compressor operation.
  39. Replace diode D102 in underhood fuse/relay center. Recheck compressor operation.

A/C Compressor Does Not Disengage

  1. Perform HVAC compressor controls system check. See A/C COMPRESSOR CLUTCH CONTROLS - ALL MODELS. Go to next step.
  2. Turn ignition switch to LOCK position. Rotate mode selector knob on main A/C-heater control module to OFF position. Ensure A/C compressor clutch is not seized. If A/C compressor clutch is seized, go to step 8) . If A/C compressor clutch is not seized, go to next step.
  3. Disconnect A/C-heater control module connector C2. Disconnect Vehicle Control Module (VCM) connector C3 (gasoline engines) or Powertrain Control Module (PCM) connector C1 (diesel engines). Turn ignition switch to ON position. Connect a test light between ground and VCM connector C3 terminal No. 25 (Dark Green/White wire) or PCM connector C1 terminal C2 (Dark Green/White wire). See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) . If test light does not come on, go to next step. If test light comes on, go to step 9) .
  4. With test light still connected, reconnect A/C-heater control module connector C2. If test light does not come on, go to next step. If test light comes on, go to step 10) .
  5. Remove A/C compressor clutch relay from underhood fuse/relay center. Disconnect A/C compressor clutch connector. Connect a test light between ground and A/C compressor clutch connector terminal "B" (Dark Green wire). If test light comes on, go to step 11) . If test light does not come on, go to next step.
  6. Reconnect VCM connector C3 (gasoline engines). Use a DVOM to check continuity between ground and A/C compressor clutch relay connector terminal C1 (Dark Green/White wire). If continuity is indicated, go to next step. If continuity is not indicated, go to step 12) .
  7. Disconnect VCM connector C3 (gasoline engines) or PCM connector C3 (diesel engines). Use a DVOM to check continuity between ground and A/C compressor clutch relay connector terminal C1 (Dark Green/White wire). If continuity is indicated, go to step 13) . If continuity is not indicated, go to step 14) .
  8. Replace A/C compressor. See «COMPRESSOR»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Recheck compressor operation.
  9. Repair short to voltage in Dark Green/White wire between A/C-heater control module and VCM (gasoline engines) or PCM (diesel engines). Recheck compressor operation.
  10. Replace main A/C-heater control module. See «A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Recheck compressor operation.
  11. Repair short to voltage in Dark Green wire between underhood fuse/relay center and A/C compressor clutch. Recheck compressor operation.
  12. Replace A/C compressor clutch relay. Recheck compressor operation.
  13. Repair short to ground in Dark Green/White wire between underhood fuse/relay center and VCM (gasoline engines) or PCM (diesel engines) connector C3. Recheck compressor operation.
  14. Replace VCM (gasoline engines) or PCM (diesel engines). See «PCM/VCM REPLACEMENT»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Recheck compressor operation.

HVAC AIR DELIVERY SYSTEM CHECK

  1. Start engine and allow to idle until operating temperature is reached. Place blower switch in high position. Place temperature control knob at full hot (Red) position. Place mode knob in defrost, blend, heater and vent positions; and allow each position to stabilize before selecting the next position. Blower motor should blow hot air at high speed from the defrost outlets when in defrost position, from defrost and floor outlets when in blend position, from floor outlets in heater position, and from the instrument panel vents in the vent position. If system does not operate as specified, go to appropriate trouble shooting procedure. Go to next step.
  2. Place temperature control knob at full cold (Blue) position. Place mode knob in same positions described in step 1) and allow each position to stabilize before selecting the next position. Blower motor should blow cooler air at high speed from appropriate outlets. If system does not operate as specified, go to appropriate trouble shooting procedure. Go to next step.
  3. Place mode control knob in MAX A/C, A/C, and bi-level positions. Blower motor should blow cold air at high speed from the instrument panel vents in MAX A/C and A/C positions, and from the vents and floor outlets in bi-level position. The A/C compressor should cycle on and off. If system does not operate as specified, go to appropriate trouble shooting procedure. For cargo van, go to next step. For passenger van, go to step 6) .
  4. Place front auxiliary A/C-heater control module blower switch in high position. Place mode select knob to lower position. Place temperature control to full hot (Red) position. Auxiliary blower motor should blow hot air at high speed from lower outlets. If system does not operate as specified, go to appropriate trouble shooting procedure. Go to next step.
  5. Place front auxiliary A/C-heater control module mode select knob to upper position. Place temperature control to full cold (Blue) position. Auxiliary blower motor should blow cold air at high speed from upper outlets. If system does not operate as specified, go to appropriate trouble shooting procedure.
  6. Place front auxiliary A/C-heater control module blower switch in high position. Place mode select knob to lower position. Place temperature control to full hot (Red) position. Auxiliary blower motor should blow hot air at high speed from lower outlets. If system does not operate as specified, go to appropriate trouble shooting procedure. Go to next step.
  7. Place front auxiliary A/C-heater control module mode select knob to upper position. Place temperature control to full cold (Blue) position. Auxiliary blower motor should blow cold air at high speed from upper outlets. If system does not operate as specified, go to appropriate trouble shooting procedure. Go to next step.
  8. Place front auxiliary A/C-heater control module mode select knob to REAR CNTL position. Place rear auxiliary A/C-heater control module blower switch in high position. Place mode select knob to lower position. Place temperature control to full cold (Blue) position. Auxiliary blower motor should blow cold air at high speed from upper outlets. If system does not operate as specified, go to appropriate trouble shooting procedure. Go to next step.
  9. Place rear auxiliary A/C-heater control module mode select knob to upper position. Place temperature control to full hot (Red) position. Auxiliary blower motor should blow hot air at high speed from lower outlets. If system does not operate as specified, go to appropriate trouble shooting procedure.

Temperature Valve Actuator Inoperative

  1. Perform «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check). Go to next step.
  2. Check that all fuses are in good condition. Disconnect Black vacuum hose at water valve. Water valve is located on right side frame rail, near center of vehicle. Connect vacuum pump to water valve. Start engine and allow it to reach operating temperature. Turn mode selector knob on main A/C-heater control module to heater position. Turn blower switch on main control module to HI position. Apply 18 in. Hg of vacuum to water valve. If blower motor produces heated air, go to next step. If blower motor does not produce heated air, go to step 14).
  3. Turn temperature control knob on main A/C-heater control module temperature control to full hot (Red) position. Connect vacuum gauge to Black vacuum hose at water valve end. If vacuum is greater than 18 in. Hg, go to step 6). If vacuum is not greater than 18 in. Hg, go to next step.
  4. Disconnect main A/C-heater control module vacuum connector. Connect vacuum gauge to Black vacuum hose (vacuum supply) at main A/C-heater control module end. If vacuum is greater than 18 in. Hg, go to next step. If vacuum is not greater than 18 in. Hg, go to step 16).
  5. Turn engine off. Disconnect White vacuum tube from main A/C-heater control module. Blow air through White vacuum hose at main A/C-heater control module. (Scheme 13) Check airflow at Black vacuum hose of water valve end. If airflow is present, go to step 17). If airflow is not present, go to step 18).
  6. Turn engine off. Reconnect all disconnected vacuum hoses. Disconnect temperature valve actuator electrical connector. Turn ignition switch to ON position. Connect a test light between ground and terminal No. 10 (Brown wire) of temperature valve actuator connector. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). If test light comes on, go to next step. If test light does not come on, go to step 19).
  7. Use a DVOM to check for continuity between ground and terminal No. 7 (Black wire) of temperature valve actuator connector. If continuity is indicated, go to next step. If continuity is not indicated, go to step 20).
  8. Connect a DVOM between ground and terminal No. 8 (Light Blue wire) of temperature valve actuator connector. Observe DVOM while moving temperature control lever on main A/C-heater control module back and forth. If voltage is not present or does not vary, go to next step. If voltage varies, go to step 21).
  9. Disconnect main A/C-heater control module (heater and A/C control module) connector C2. Connect test light between ground and terminal "E" (Brown wire) of connector C2. If test light comes on, go to next step. If test light does not come on, go to step 23).
  10. Disconnect main A/C-heater control module (heater and A/C control module) connector C1. Use a DVOM to check for continuity between ground and terminal "B" (Black wire) of connector C1. If continuity is indicated, go to next step. If continuity is not indicated, go to step 24).
  11. Connect a test light between ground and terminal "F" (Light Blue wire) of main A/C-heater control module connector C2. If test light comes on, go to step 25). If test light does not come on, go to next step.
  12. Ensure ignition switch is off. Use a DVOM to check for continuity between ground and terminal "F" (Light Blue wire) of main A/C-heater control module connector C2. If continuity is indicated, go to step 26). If continuity is indicated, go to next step.
  13. Use a DVOM to check for continuity between terminal "F" of main A/C-heater control module connector C2 and terminal No. 8 of temperature valve actuator connector (Light Blue wire). If continuity is indicated, go to step 17). If continuity is not indicated, go to step 27).
  14. Check for engine coolant flow restriction through heater hoses and core. Repair as necessary. If coolant is not restricted/obstructed, go to next step. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  15. Replace temperature valve. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  16. Check for loose hose connection or leaking/crimped vacuum supply hose from engine to main A/C-heater control module. Check vacuum supply tank located on right front fender, under battery. Repair as necessary. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  17. Replace main A/C-heater control module. See «A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  18. Check for loose hose connection or leaking/crimped vacuum hoses from main A/C-heater control module (White hose) to water valve (Black hose). (Scheme 13) Repair as necessary. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  19. Repair open in Brown wire between instrument module fuse block and actuator connector. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  20. Repair open in Black wire between temperature valve actuator and ground. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  21. Check mechanical functions of temperature valve (door). Repair as necessary. If temperature valve (door) is okay, go to next step. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  22. Replace temperature valve actuator. See «ACTUATORS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  23. Repair open in Brown wire between main A/C-heater control module and splice S215. Splice S215 is located in instrument panel harness, approximately 1.6" (4 cm) from radio breakout going toward power antenna. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  24. Repair open in Black wire between main A/C-heater control module and splice S202. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  25. Repair short to voltage in Light Blue wire between main A/C-heater control module and temperature valve actuator. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  26. Repair short to ground in Light Blue wire between main A/C-heater control module and temperature valve actuator. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  27. Repair open in Light Blue wire between main A/C-heater control module and temperature valve actuator. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).

Temperature Valve & Mode Valve Assemblies Inoperative

  1. Perform «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check). Go to next step.
  2. Turn ignition switch to ON position. Disconnect front auxiliary A/C-heater control module connector, located in overhead console. Connect test light between ground and terminal "G" (Brown wire) of front auxiliary A/C-heater control module connector. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). If test light comes on, go to next step. If test light does not come on, go to step 5).
  3. Disconnect auxiliary temperature valve assembly connector. (Scheme 2) Connect a test light between ground and terminal No. 10 (Brown wire) of auxiliary temperature valve assembly connector. If test light comes on, go to next step. If test light does not come on, go to step 6).
  4. Use a DVOM to check continuity between ground and terminal No. 7 (Black wire) of auxiliary temperature valve assembly connector. If continuity is indicated, go to step 7). If continuity is not indicated, go to step 8).
  5. Repair open in Brown wire between instrument panel fuse block and front auxiliary A/C-heater control module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  6. Repair open in Brown wire between instrument panel fuse block and splice S405. Splice S405 is located in rear A/C harness, approximately 2.8" (7 cm) from auxiliary blower motor resistor breakout. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  7. Replace front auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  8. Repair open in Black wire between ground and splice S411. Splice S411 is located in rear A/C wiring harness, approximately 5" (13 cm) from blower motor breakout. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).

Temperature Valve Assembly Inoperative

  1. Perform «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check). Go to next step.
  2. Turn ignition switch to ON position. Disconnect auxiliary temperature valve assembly connector. (Scheme 2) Connect a test light between ground and terminal No. 10 (Brown wire) of auxiliary temperature valve assembly connector. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). If test light comes on, go to next step. If test light does not come on, go to step 8).
  3. Use a DVOM to check continuity between ground and terminal No. 7 (Black wire) of auxiliary temperature valve assembly connector. If continuity is indicated, go to next step. If continuity is not indicated, go to step 9).
  4. Place front auxiliary A/C-heater control module in OFF position. Connect a DVOM between ground and terminal No. 8 (Dark Green wire) of auxiliary temperature valve connector. Observe DVOM while adjusting temperature control on front auxiliary A/C-heater control module. If voltage varies, go to step 10). If voltage is not present or does not vary, go to next step.
  5. Disconnect front auxiliary A/C-heater control module connector. Connect a test light between ground and terminal "H" (Dark Green wire) of front auxiliary A/C-heater control module connector. If test light comes on, go to step 11). If test light does not come on, go to next step.
  6. Use a DVOM to check continuity between ground and front auxiliary A/C-heater control module connector terminal "B" (Black wire). If continuity is indicated, go to step 12). If continuity is not indicated, go to next step.
  7. Connect a fused jumper wire between ground and terminal No. 8 (Dark Green wire) of auxiliary temperature valve assembly connector. Use a DVOM to check continuity between ground and terminal "H" (Dark Green wire) of front auxiliary A/C-heater control module connector. If continuity is indicated, go to step 13). If continuity is not indicated, go to step 14).
  8. Repair open in Brown wire between auxiliary temperature valve assembly and splice S405. Splice S405 is located in rear A/C harness, approximately 2.8" (7 cm) from auxiliary blower motor resistor breakout. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  9. Repair open in Black wire between auxiliary temperature valve assembly and splice S411. Splice S411 is located in rear A/C wiring harness, approximately 5" (13 cm) from blower motor breakout. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  10. Replace auxiliary temperature valve assembly. (Scheme 2) Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  11. Repair short to voltage in Dark Green wire between front auxiliary A/C-heater control module and auxiliary temperature valve assembly. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  12. Repair short to ground in Black wire between front auxiliary A/C-heater control module and auxiliary temperature valve assembly. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  13. Replace front auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  14. Repair open in Dark Green wire between rear auxiliary A/C-heater control module and auxiliary temperature valve assembly. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).

Mode Valve Inoperative

  1. Perform «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check). Go to next step.
  2. Turn ignition switch to ON position. Disconnect auxiliary mode valve and seal assembly connector. (Scheme 2) Connect a test light between ground and terminal No. 10 (Brown wire) of auxiliary mode valve and seal assembly connector. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). If test light comes on, go to next step. If test light does not come on, go to step 8).
  3. Use a DVOM to check continuity between ground and terminal No. 7 (Black wire) of auxiliary mode valve and seal assembly connector. If continuity is indicated, go to next step. If continuity is not indicated, go to step 9).
  4. Turn front auxiliary A/C-heater control module to OFF position. Connect a DVOM between ground and terminal No. 8 (Light Blue wire) of auxiliary mode valve and seal connector. Observe DVOM while moving mode control knob on rear auxiliary A/C-heater control module. If voltage varies, go to step 10). If voltage is not present or does not vary, go to next step.
  5. Disconnect front auxiliary A/C-heater control module connector. Connect a test light between ground and terminal "J" (Light Blue wire) of front auxiliary A/C-heater control module connector. If test light comes on, go to step 11). If test light does not come on, go to next step.
  6. Use a DVOM to check continuity between ground and terminal "J" (Light Blue wire) of front auxiliary A/C-heater control module connector. If continuity is indicated, go to step 12). If continuity is not indicated, go to next step.
  7. Connect fused jumper wire between ground and terminal No. 8 (Light Blue wire) of auxiliary mode valve and seal assembly connector. Connect a self-powered test light between ground and terminal "J" (Light Blue wire) of front auxiliary A/C-heater control module connector. If test light comes on, go to step 13). If test light does not come on, go to step 14).
  8. Repair open in Brown wire between auxiliary mode valve and seal assembly and splice S405. Splice S405 is located in rear A/C harness, approximately 2.8" (7 cm) from auxiliary blower motor resistor breakout. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  9. Repair open in Black wire between auxiliary mode valve and seal assembly and splice S411. Splice S411 is located in rear A/C wiring harness, approximately 5" (13 cm) from blower motor breakout. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  10. Replace auxiliary mode valve and seal assembly. (Scheme 2) Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  11. Repair short to voltage in Light Blue wire between front auxiliary A/C-heater control module and auxiliary mode valve and seal assembly. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  12. Repair short to ground in Light Blue wire between front auxiliary A/C-heater control module and auxiliary mode valve and seal assembly. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  13. Replace front auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  14. Repair open in Light Blue wire between front auxiliary A/C-heater control module and auxiliary mode valve and seal assembly. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).

Mode And Temperature Valves Inoperative

  1. Perform «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check). Go to next step.
  2. Ensure all fuses are in good conditions and all ground connections are secure. Disconnect front auxiliary A/C-heater control module connector. Turn ignition switch to ON position. Connect a test light between ground and terminal "G" (Brown wire) of front auxiliary A/C-heater control module connector. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). If test light comes on, go to next step. If test light does not come on, go to step 26).
  3. Disconnect auxiliary temperature valve assembly connector. (Scheme 2) Connect a test light between ground and terminal No. 10 (Brown wire) of auxiliary temperature valve assembly connector. If test light comes on, go to next step. If test light does not come on, go to step 27).
  4. Use a DVOM to check for continuity between ground and terminal No. 7 (Black wire) of the auxiliary temperature valve assembly connector. If continuity is indicated, go to next step. If continuity is not indicated, go to step 28).
  5. If auxiliary mode and temperature valves can be controlled from rear auxiliary A/C-heater control module, go to next step. If auxiliary mode and temperature valves cannot be controlled from rear auxiliary A/C-heater control module, go to step 14).
  6. Reconnect front auxiliary A/C-heater control module connector. Disconnect A/C-heater control logic module connector. Connect a DVOM between ground and terminal "A" (Dark Green wire) of A/C-heater control logic module connector. Observe DVOM while adjusting temperature control on front auxiliary A/C-heater control module. If voltage is present and varies, go to step 10). If voltage is not present or does not vary, go to next step.
  7. Disconnect front auxiliary A/C-heater control module connector. Connect test light between ground and terminal "H" (Dark Green wire) of front auxiliary A/C-heater control module connector. If test light comes on, go to step 29). If test light does not come on, go to next step.
  8. Use a DVOM to check for continuity between ground and terminal "H" (Dark Green wire) of front auxiliary A/C-heater control module connector. If continuity is indicated, go to step 30). If continuity is not indicated, go to next step.
  9. Use a DVOM to check for continuity between terminal "H" (Dark Green wire) of front auxiliary A/C-heater control module connector and terminal "A" (Dark Green wire) of A/C-heater control logic module connector. If continuity is indicated, go to step 31). If continuity is not indicated, go to step 32).
  10. Connect a DVOM between ground and terminal "E" (Light Blue wire) of A/C-heater control logic module connector. Observe DVOM while moving mode control knob on front auxiliary A/C-heater control module. If voltage is present and varies, go to step 33). If voltage is not present or does not vary, go to next step.
  11. Disconnect front auxiliary A/C-heater control module connector. Connect a test light between ground and terminal "J" (Light Blue wire) of front auxiliary A/C-heater control module connector. If test light comes on, go to step 34). If test light does not come on, go to next step.
  12. Use a DVOM to check for continuity between ground and terminal "J" (Light Blue wire) of front auxiliary A/C-heater control module connector. If continuity is indicated, go to step 35). If continuity is not indicated, go to next step.
  13. Use a DVOM to check for continuity between terminal "J" (Light Blue wire) of front auxiliary A/C-heater control module connector and terminal "E" (Light Blue wire) of A/C-heater control logic module connector. If continuity is indicated, go to step 31). If continuity is not indicated, go to step 36).
  14. Reconnect front auxiliary A/C-heater control module connector. Disconnect A/C-heater control logic module connector. Connect test light between A/C-heater control logic module connector terminal "J" (Brown wire) and ground. If test light comes on, go to next step. If test light does not come on, go to step 37).
  15. Place front auxiliary A/C-heater control module blower switch in REAR CNTL position. Use a DVOM to check for continuity between ground and terminal "M" (Light Blue wire) of A/C-heater control logic module connector. If continuity is indicated, go to step 17). If continuity is not indicated, go to next step.
  16. Disconnect front auxiliary A/C-heater control module connector. Use a DVOM to check for continuity between terminal "M" (Light Blue wire) of A/C-heater control logic module connector and terminal "F" (Light Blue wire) of front auxiliary A/C-heater control module connector. If continuity is indicated, go to step 31). If continuity is not indicated, go to step 38).
  17. Disconnect rear auxiliary A/C-heater control module connector. Connect a test light between ground and terminal "G" (Brown wire) of rear auxiliary A/C-heater control module connector. If test light comes on, go to next step. If test light does not come on, go to step 39).
  18. Reconnect rear auxiliary A/C-heater control module connector. Connect a DVOM between ground and terminal "C" (Dark Green wire) of A/C-heater control logic module connector. Observe DVOM while adjusting temperature control on rear auxiliary A/C-heater control module. If voltage is present and varies, go to step 22). If voltage is not present or does not vary, go to next step.
  19. Disconnect rear auxiliary A/C-heater control module connector. Connect a test light between ground and terminal "H" (Dark Green wire) of rear auxiliary A/C-heater control module connector. If test light comes on, go to step 40). If test light does not come on, go to next step.
  20. Use a DVOM to check for continuity between ground and terminal "H" (Dark Green wire) of rear auxiliary A/C-heater control module connector. If continuity is indicated, go to step 41). If continuity is not indicated, go to next step.
  21. Use a DVOM to check for continuity between terminal "H" (Dark Green wire) of rear auxiliary A/C-heater control module connector and terminal "C" (Dark Green wire) of A/C-heater control logic module connector. If continuity is indicated, go to step 42). If continuity is not indicated, go to step 43).
  22. Connect a DVOM between ground and terminal "D" (Light Blue wire) of A/C-heater control logic module connector. Observe DVOM while moving mode control knob on rear auxiliary A/C-heater control module. If voltage is present and varies, go to step 33). If voltage is not present or does not vary, go to next step.
  23. Disconnect rear auxiliary A/C-heater control module connector. Connect a test light between ground and terminal "J" (Light Blue wire) of rear auxiliary A/C-heater control module connector. If test light comes on, go to step 44). If test light does not come on, go to next step.
  24. Use a DVOM to check for continuity between ground and terminal "J" (Light Blue wire) of rear auxiliary A/C-heater control module connector. If continuity is indicated, go to step 45). If continuity is not indicated, go to next step.
  25. Use a DVOM to check for continuity between terminal "J" (Light Blue wire) of rear auxiliary A/C-heater control module connector and terminal "D" (Light Blue wire) of A/C-heater control logic module connector. If continuity is indicated, go to step 42). If continuity is not indicated, go to step 46).
  26. Repair open in Brown wire between front auxiliary A/C-heater control module and splice S307. Splice S307 is located in auxiliary A/C-heater harness, approximately 13" (33 cm) from rear auxiliary A/C-heater control module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  27. Repair open in Brown wire between auxiliary temperature valve assembly and splice S404. Splice S404 is located in left body harness, approximately 13" (33 cm) from connector C409 breakout, toward connector C417 breakout. Connector C409 is located in front of front headliner on driver's side. Connector C417 is located in center of vehicle, under headliner on driver's side. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  28. Repair open in Black wire between ground and splice S411. Splice S411 is located in rear A/C wiring harness approximately 5" (13 cm) from blower motor breakout. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  29. Repair short to voltage in Dark Green wire between front auxiliary A/C-heater control module and auxiliary A/C-heater control logic module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  30. Repair short to ground in Dark Green wire between front auxiliary A/C-heater control module and auxiliary A/C-heater control logic module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  31. Replace front auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  32. Repair open in Dark Green wire between front auxiliary A/C-heater control module and auxiliary A/C-heater control logic module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  33. Replace auxiliary A/C-heater control logic module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  34. Repair short to voltage in Light Blue wire between front auxiliary A/C-heater control module and auxiliary A/C-heater control logic module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  35. Repair short to ground in Light Blue wire between front auxiliary A/C-heater control module and auxiliary A/C-heater control logic module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  36. Repair open in Light Blue wire between front auxiliary A/C-heater control module and auxiliary A/C-heater control logic module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  37. Repair open in Brown wire between A/C-heater control logic module and splice S307. Splice S307 is located in auxiliary A/C-heater harness, approximately 13" (33 cm) from rear auxiliary A/C-heater control module, toward front auxiliary A/C-heater control module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  38. Repair open in Light Blue wire between A/C-heater control logic module and front auxiliary A/C-heater control module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  39. Repair open in Brown wire between rear auxiliary A/C-heater control module and splice S307. Splice S307 is located in auxiliary A/C-heater harness, approximately 13" (33 cm) from rear auxiliary A/C-heater control module, toward front auxiliary A/C-heater control module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  40. Repair short to voltage in Dark Green wire between rear auxiliary A/C-heater control module and auxiliary A/C-heater control logic module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  41. Repair short to ground in Dark Green wire between rear auxiliary A/C-heater control module and auxiliary A/C-heater control logic module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  42. Replace rear auxiliary A/C-heater control module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  43. Repair open in Dark Green wire between rear auxiliary A/C-heater control module and auxiliary A/C-heater control logic module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  44. Repair short to voltage in Light Blue wire between rear auxiliary A/C-heater control module and auxiliary A/C-heater control logic module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  45. Repair short to ground in Light Blue wire between rear auxiliary A/C-heater control module and auxiliary A/C-heater control logic module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  46. Repair open in Light Blue wire between rear auxiliary A/C-heater control module and auxiliary A/C-heater control logic module. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  1. Perform «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check). Go to next step.
  2. Turn ignition switch to ON position. Disconnect auxiliary temperature valve assembly connector. (Scheme 2) Connect a test light between ground and terminal No. 10 (Brown wire) of auxiliary temperature valve assembly connector. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). If test light comes on, go to next step. If test light does not come on, go to step 8).
  3. Connect a self-powered test light between ground and terminal No. 7 (Black wire) of auxiliary temperature valve assembly connector. If test light comes on, go to next step. If test light does not come on, go to step 9).
  4. Place blower switch on front auxiliary A/C-heater control module in OFF position. Connect a DVOM between ground and terminal No. 8 (Dark Green wire) of auxiliary temperature valve assembly connector. Observe DVOM while adjusting temperature control on front auxiliary A/C-heater control module. If voltage varies, go to step 10). If voltage is not present or does not vary, go to next step.
  5. Disconnect A/C-heater control logic module connector. Connect a test light between ground and terminal "B" (Dark Green wire) of A/C-heater control logic module connector. If test light comes on, go to step 11). If test light does not come on, go to next step.
  6. Connect a self-powered test light between ground and terminal "B" (Dark Green wire) of A/C-heater control logic module connector. If test light comes on, go to step 12). If test light does not come on, go to next step.
  7. Connect fused jumper wire between ground and terminal No. 8 (Dark Green wire) of auxiliary temperature valve assembly connector. Connect a self-powered test light between ground and terminal "B" (Dark Green wire) of A/C-heater control logic module connector. If test light comes on, go to step 13). If test light does not come on, go to step 14).
  8. Repair open in Brown wire between auxiliary temperature valve assembly and splice. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  9. Repair open in Black wire between auxiliary temperature valve assembly and splice. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  10. Replace auxiliary temperature valve assembly. (Scheme 2) Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  11. Repair short to voltage in Dark Green wire between A/C-heater control logic module and auxiliary temperature valve assembly. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  12. Repair short to ground in Dark Green wire between A/C-heater control logic module and auxiliary temperature valve assembly. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  13. Replace auxiliary A/C-heater control logic module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  14. Repair open in Dark Green wire between A/C-heater control logic module and auxiliary temperature valve assembly. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).

Mode Valve Assembly Inoperative

  1. Perform «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check). Go to next step.
  2. Turn ignition switch to ON position. Disconnect auxiliary mode valve and seal assembly connector. (Scheme 2) Connect a test light between ground and terminal No. 10 (Brown wire) of auxiliary mode valve and seal assembly connector. See «WIRING DIAGRAMS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). If test light comes on, go to next step. If test light does not come on, go to step 8).
  3. Use a DVOM to check for continuity between ground and terminal No. 7 (Black wire) of auxiliary mode valve and seal assembly connector. If continuity is indicated, go to next step. If continuity is not indicated, go to step 9).
  4. Place blower motor control knob on front auxiliary A/C-heater control module in OFF position. Connect DVOM between ground and terminal No. 8 (Light Blue wire) of auxiliary mode valve and seal assembly connector. Observe DVOM while moving mode control knob on front auxiliary A/C-heater control module. If voltage is present and varies, go to step 10). If voltage is not present or does not vary, go to next step.
  5. Disconnect A/C-heater control logic module connector. Connect test light between ground and terminal "F" (Light Blue wire) of A/C-heater control logic module connector. If test light comes on, go to step 11). If test light does not come on, go to next step.
  6. Connect a self-powered test light between ground and terminal "F" (Light Blue wire) of A/C-heater control logic module connector. If test light comes on, go to step 12). If test light does not come on, go to next step.
  7. Connect a fused jumper wire between ground and terminal No. 8 (Light Blue wire) of auxiliary mode valve and seal assembly connector. Connect a self-powered test light between ground and terminal "F" (Light Blue wire) of A/C-heater control logic module connector. If test light comes on, go to step 13). If test light does not come on, go to step 14).
  8. Repair open in Brown wire between auxiliary mode valve and seal assembly and splice S405. Splice S405 is located in rear A/C harness, approximately 2.8" (7 cm) from auxiliary blower motor resistor breakout. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  9. Repair open in Black wire between auxiliary mode valve and seal assembly and splice S411. Splice S411 is located in rear A/C wiring harness, approximately 5" (13 cm) from blower motor breakout. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  10. Replace auxiliary mode valve and seal assembly. (Scheme 2) Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  11. Repair short to voltage in Light Blue wire between A/C-heater control logic module and auxiliary mode valve and seal assembly. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  12. Repair short to ground in Light Blue wire between A/C-heater control logic module and auxiliary mode valve and seal assembly. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  13. Replace auxiliary A/C-heater control logic module. See «AUXILIARY A/C-HEATER CONTROL MODULE»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) under REMOVAL & INSTALLATION. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).
  14. Repair open in Light Blue wire between A/C-heater control logic module and auxiliary mode valve and seal assembly. Go to «HVAC AIR DELIVERY SYSTEM CHECK»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system__hvac-air-delivery-system-check).

A/C SYSTEM PERFORMANCE

  1. Park vehicle out of direct sunlight. Open windows and doors to ventilate interior. Vent engine exhaust, if necessary. Open engine hood, and install manifold gauge set. Route lines over rear hood seal, and tape gauge set to windshield for viewing. Close engine hood.
  2. Note ambient temperature and relative humidity. Close all windows and doors. Set climate controls in A/C, full COLD setting, and blower motor on high speed. Open A/C outlets. Insert thermometer into right center A/C outlet. Place transmission in Park.
  3. Start engine and allow it to run at 1500 RPM until lowest temperature is reached (approximately 10 minutes). Record high-side and low-side pressures. Record discharge air temperature at right center A/C outlet. Compare readings with specifications. See «A/C SYSTEM SPECIFICATIONS»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system) table.
Ambient Temp. °F (°C)Low-Side Pressure psi (kg/cm 2 )High-Side Pressure psi (kg/cm 2 )Outlet Air Temp. °F (°C)
80 (27)32 (2.2)228 (16.0)51 (11)
90 (32)39 (2.7)280 (19.7)59 (15)
100 (38)44 (3.1)301 (21.2)66 (19)
110 (43)46 (3.2)327 (13.1)75 (24)
(1) Specifications are with relative humidity at 40 percent.
(1)Specifications are with relative humidity at 40 percent.

A/C SYSTEM SPECIFICATIONS (1)

REMOVAL & INSTALLATION

WARNINGTo avoid injury from accidental air bag deployment, read and carefully follow all SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM procedures in AIR BAG SYSTEM SAFETY article in GENERAL SERVICING.

Note. For removal & installation procedures not covered, see HEATER SYSTEMS - RWD TRUCKS & VANS - EXCEPT TRACKER article.

  1. Disconnect negative battery cable. Ensure parking brake is set. Place steering column shifter 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 the 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.

Removal & Installation (Main Temperature Actuator)

Main temperature valve actuator motor is located on A/C-heater assembly, on passenger's side, between the 2 vacuum actuators. Disconnect actuator electrical connector and remove 3 screws attaching to A/C-heater assembly. Remove actuator from vehicle. To install, reverse removal procedure.

Removal & Installation (Auxiliary Actuators)

  1. Disconnect negative battery cable. 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 the top and lower edge of left rear side window. Remove rear pillar panel.
  2. Disconnect electrical connector from appropriate actuator and remove screws attaching actuator to auxiliary A/C-heater assembly. (Scheme 6) To install, reverse removal procedure.

Scheme 6

Scheme 6
Scheme 6

Removal

  1. Disconnect battery cables. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Drain coolant recovery tank. Remove battery. Remove orifice retainer from blower motor insulating cover. Remove insulating cover. (Scheme 12)
  2. Disconnect A/C lines from accumulator and plug openings. Disconnect electrical connectors (if necessary). Remove accumulator and bracket. (Scheme 7) Drain oil from accumulator into measuring container, and note amount for installation reference.

Installation

To install, reverse removal procedure. Add equal amount of oil drained plus one ounce of clean refrigerant oil to new accumulator. Install new "O" rings lubricated with clean refrigerant oil. Evacuate, charge, and leak test A/C system.

Scheme 7

Scheme 7: Installation
Scheme 7: Installation

Removal & Installation (Front & Rear Overhead Console & Auxiliary A/C-Heater Control Logic Module)

Auxiliary A/C-heater control logic module is located and accessed through front auxiliary A/C-heater control module opening. Remove control panel bezel and control panel assembly of desired control panel. Disconnect electrical connectors and remove control panel. To install, reverse removal procedure.

BLOWER MOTORS

Note. For non-auxiliary system blower motor removal and installation procedures, see BLOWER MOTOR under REMOVAL & INSTALLATION in HEATER SYSTEMS - RWD TRUCKS & VANS - EXCEPT TRACKER article.

Removal & Installation (Auxiliary System)

  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. Blower motor resistor is located next to blower motor and can be removed without removing auxiliary heater assembly.
  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 11) Separate blower motor plate from heater case. Remove cover screws and cover. Unplug connector(s) from blower motor. Remove blower motor. To install, reverse removal procedure. Fill cooling system. Start engine and check for leaks.
  1. Disconnect negative battery cable. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Disconnect electrical connectors. Remove engine cover. Remove drive belt. Remove oil filler tube.
  2. Remove compressor and condenser hose assembly, and cap openings. (Scheme 8)and (Scheme 9). Remove compressor brace and compressor. Drain oil from compressor into measuring container, and note amount drained for installation reference.

If amount drained is less than one ounce, add 2 ounces of clean refrigerant to new compressor. If amount drained is more than one ounce, add same amount to new compressor. To install, reverse removal procedure. Evacuate, charge, and leak test A/C system.

Scheme 8

Scheme 8: Installation
Scheme 8: Installation

Scheme 9

Scheme 9
Scheme 9
  1. Disconnect negative battery cable. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Remove radiator grille. Remove push-pins retaining hood latch cover to radiator support. Remove hood latch cover and latch. Remove left headlight housing. Disconnect lines at condenser, and cap openings. Remove condenser bolts and condenser.
  2. To install, reverse removal procedure. Install new "O" rings lubricated with clean refrigerant oil. Add one ounce of clean refrigerant oil to condenser. Evacuate, charge, and leak test A/C system.
  1. Disconnect negative battery cable. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Remove left rear trim panel. Remove air outlet ducts.
  2. Disconnect electrical connectors. Remove auxiliary evaporator tube assembly from evaporator core. (Scheme 10) Remove 4 bolts retaining auxiliary A/C-heater assembly. Remove assembly. (Scheme 11) Separate case halves. Remove core seal. Remove evaporator core.
  3. To install, reverse removal procedure. Replace gaskets and seals if damaged. Install new "O" rings lubricated with clean refrigerant oil. Add 3 ounces of clean refrigerant oil to new core. Evacuate, charge, and leak test A/C system.

Scheme 10

Scheme 10
Scheme 10

Scheme 11

Scheme 11
Scheme 11

Removal & Installation (Main System)

  1. Disconnect battery cables, and remove battery. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Drain engine coolant. Remove coolant recovery tank and bracket. Disconnect all electrical connectors from A/C-heater assembly.
  2. Remove accumulator. See «ACCUMULATOR»(/gmc/savana/i-1996-2002/remont/manual-hvac-system/#hvac-system). Disconnect evaporator tube from evaporator. Remove "O" ring. Disconnect evaporator tube from condenser. Remove "O" ring. Disconnect evaporator tube from auxiliary evaporator underbody front tube assembly.
  3. Remove insulator cover. Remove A/C-heater assembly cover bolts/nuts. Separate case halves. Remove nut retaining A/C-heater assembly to vehicle. Remove A/C-heater assembly. (Scheme 12) Remove evaporator core.
  4. To install, reverse removal procedure. Install new "O" rings lubricated with clean refrigerant oil. Add 3 ounces of clean refrigerant oil to new condenser. Evacuate, charge, and leak test A/C system.

Scheme 12

Scheme 12
Scheme 12

EXPANSION VALVE

Note. Expansion valve is used on auxiliary units which do not use external equalizer line.

  1. Disconnect negative battery cable. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Gently remove sealer packed around expansion valve. Remove clip retaining capillary tube to evaporator core. Note location and orientation of tube for installation reference. Remove 2 nuts retaining expansion valve to evaporator core. Remove expansion valve.
  2. To install, reverse removal procedure. Install new "O" rings lubricated with clean refrigerant. Ensure capillary tube properly contacts core outlet line. Evacuate, charge, and leak test A/C system.

Disconnect negative battery cable. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Disconnect connector to switch. Remove switch using snap-ring pliers. Remove switch and discard "O" ring. Use new "O" ring on switch and coat with fresh refrigerant oil. To install, reverse removal procedure.

Removal & Installation (PCM - Diesel Engines)

  1. Locate PCM above engine cover, below center of instrument panel. Remove instrument panel lower extension upper trim, below radio, in center of instrument panel, by pulling downward to disengage clips. Remove 7 bolts attaching center console to engine cover. Disconnect 3 electrical connectors and remove center console from engine cover.
  2. Remove passenger seat from vehicle by removing bolts/nuts attaching seal rail assembly to floor. Remove 4 engine cover retaining straps and remove engine cover from vehicle. Disconnect 3 connectors from PCM and remove PCM mounting nuts. Remove PCM mounting hardware from PCM.
  3. To install, reverse removal procedure. Ensure PCM wiring harness does not get pinched when reinstalling engine cover. Program PCM. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION in ENGINE PERFORMANCE - DOMESTIC CARS, LIGHT TRUCKS & VANS manual.

Removal & Installation (VCM - Gasoline Engines)

  1. Locate VCM in engine compartment. Disconnect negative battery cable. Remove spring retainers for VCM module-to-bracket mounting. Remove VCM and disconnect electrical connectors. Remove access cover screws to access knock sensor module. Pinch retaining clip to remove module from VCM. Place module in a safe place for reuse in new VCM.
  2. Verify that replacement VCM number is identical to original VCM. Reinstall knock sensor module in replacement VCM and reinstall VCM cover plate. Reconnect VCM connectors and reinstall VCM into bracket. Secure VCM with spring clips and program VCM. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION in ENGINE PERFORMANCE - DOMESTIC CARS, LIGHT TRUCKS & VANS manual.

TORQUE SPECIFICATIONS

ApplicationFt. Lbs. (N.m)
A/C Compressor Bolt37 (50)
Compressor Brace-To-Generator Bracket Bolt18 (25)
Refrigerant Hoses
Accumulator-to-Evaporator Outlet Tube35 (48)
Auxiliary Hose-To-Compressor Bolt33 (45)
Auxiliary Evaporator Tube-To-Evaporator Tube Fitting21 (28)
Compressor/Condenser Tube-To-Accumulator Fitting35 (48)
Compressor/Condenser Tube-To-Compressor Bolt33 (45)
Compressor/Condenser Tube-To-Condenser Fitting21 (28)
Evaporator Inlet Tube-To-Condenser Fitting21 (28)
Evaporator Inlet Tube-To-Evaporator Fitting14 (19)
INCH Lbs. (N.m)
Accumulator Bracket Screw53 (6)
Condenser Bolt89 (10)
Evaporator Nut53 (6)
Heater Unit
Auxiliary89 (10)
Main53 (6)
Vacuum Tank-To-Battery Tray Bolts97 (11)

TORQUE SPECIFICATIONS

Scheme 13

Scheme 13: VACUUM HOSE DIAGRAM(S)
Scheme 13: VACUUM HOSE DIAGRAM(S)

Manual A/C-Heater System Wiring Diagram ("G" 1500/3500, Express & Savana - Cargo Van - Except Diesel). Scheme 14

Scheme 14: Manual A/C-Heater System Wiring Diagram ("G" 1500/3500, Express & Savana - Cargo Van - Except Diesel)
Scheme 14: Manual A/C-Heater System Wiring Diagram ("G" 1500/3500, Express & Savana - Cargo Van - Except Diesel)

Manual A/C-Heater System Wiring Diagram ("G" 2500/3500, Express & Savana - Cargo Van - Diesel). Scheme 15

Scheme 15: Manual A/C-Heater System Wiring Diagram ("G" 2500/3500, Express & Savana - Cargo Van - Diesel)
Scheme 15: Manual A/C-Heater System Wiring Diagram ("G" 2500/3500, Express & Savana - Cargo Van - Diesel)

Manual A/C-Heater System Wiring Diagram ("G" 1500/3500, Express & Savana - Passenger Van - Except Diesel). Scheme 16

Scheme 16: Manual A/C-Heater System Wiring Diagram ("G" 1500/3500, Express & Savana - Passenger Van - Except Diesel)
Scheme 16: Manual A/C-Heater System Wiring Diagram ("G" 1500/3500, Express & Savana - Passenger Van - Except Diesel)

Manual A/C-Heater System Wiring Diagram ("G" 1500/3500, Express & Savana - Passenger Van - Diesel). Scheme 17

Scheme 17: Manual A/C-Heater System Wiring Diagram ("G" 1500/3500, Express & Savana - Passenger Van - Diesel)
Scheme 17: Manual A/C-Heater System Wiring Diagram ("G" 1500/3500, Express & Savana - Passenger Van - Diesel)

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