HVAC System - Automatic: Other Oldsmobile Eighty-Eight X

A/C-HEATER CONTROL PANEL

Buttons on the A/C-heater control panel select operating modes and ambient (outside) air temperature display. Two increase/decrease knobs control in-vehicle temperature and blower motor speed. A passenger-side control panel allows the front seat passenger to adjust temperature setting.

PROGRAMMER

The programmer processes electrical signals from the A/C-heater control panel, passenger-side control panel, air temperature sensors, sunload sensors, blower motor control module, PCM and air mix door (valve) actuators to control air intake door actuator, distribution door actuator, and blower motor.

OFF Button

When OFF button is pressed, blower motor will be at minimum calibrated speed and A/C compressor will be off. Programmer will allow all vacuum actuators to vent. Outside/recirculated air door will be in outside air position, bi-level door will be in BI-LEVEL position, and defrost door will be in defrost position. Forward motion of vehicle will force air through A/C-heater system and out through floor and windshield outlets. Temperature control system is still activated and will attempt to match in-vehicle and selected temperature. Because compressor is not operating, in-vehicle air can only be warmed, not cooled.

AUTO Button

When AUTO button is pressed, AUTO and SET temperature indicators will come on. Blower motor speed indicators will go off, indicating automatic control. Blower motor speed can be controlled using fan speed control knob. Programmer will evaluate inputs and determine which mode is required to maintain SET temperature.

A/C Button

A/C button controls compressor operation in manual mode. A/C LED will come on when A/C, DEFOG or FRONT DEFROST button is pressed. A/C system operation cannot be deselected during DEFOG or FRONT DEFROST operation. If Diagnostic Trouble Code (DTC) 48 is present, A/C system and A/C LED will not operate.

UPPER Button

When UPPER button is pressed, UPPER LED will come on, and selected temperature will be displayed for 5 seconds. Blower motor operates, and speed can be manually controlled using control knob. Programmer applies vacuum to defrost A/C door vacuum actuator and one side of heater-A/C-bi-level vacuum door actuator. see scheme 7 Outside/recirculated air door actuator is in outside air position. Defrost-A/C door actuator and heater-A/C-bi-level door actuator are in A/C position. Programmer will direct air from vent outlets.

BI-LEV Button

When BI-LEV button is pressed, BI-LEV LED will come on and SET temperature will be displayed for 5 seconds. Programmer applies vacuum to one side of heater-A/C-bi-level vacuum actuator, with remaining actuators venting. Outside/recirculated air door is in outside air position, defrost-A/C door is in defrost position, and heater-A/C-bi-level door is in A/C position. Outside air will be cooled, dehumidified and heated as necessary. Programmer will direct air through the instrument panel and the lower (floor) outlets. see scheme 7

LOWER Button

When LOWER button is pressed, LOWER LED will come on, and selected temperature will be displayed for 5 seconds. Blower motor operates, and speed can be manually controlled using control knob. Pressing A/C button will activate compressor if ambient temperature is more than 45-50°F (7-10°C); compressor will run to maintain evaporator temperature at 33°F (1°C). Programmer applies vacuum to one side of heater-A/C-bi-level vacuum actuator, with remaining actuators venting. see scheme 7 Outside/recirculated air door is in outside air position, defrost-A/C door is in defrost position, and heater-A/C-bi-level door is in heater position. Programmer will direct air from lower (floor) outlets.

DEFOG Button

When DEFOG button is pressed, DEFOG LED and A/C LED will come on, and selected temperature will be displayed for 5 seconds. Compressor will be activated if ambient temperature is more than 48°F (9°C) and will run to maintain evaporator temperature at 33°F (1°C). Outside air will be cooled, dehumidified and heated as necessary. Programmer will direct air from lower (floor) and defrost outlets.

FRONT DEFROST Button

When FRONT DEFROST button is pressed, FRONT DEFROST LED and A/C LED will come on, and selected temperature will be displayed for 5 seconds. Compressor will be activated if ambient temperature is more than 48°F (9°C) and will run to maintain evaporator temperature at 33°F (1°C). Blower motor is manually controlled. Programmer applies vacuum to one side of heater-A/C-bi-level vacuum actuator, with remaining actuators venting. Outside/recirculated air door is in outside air position, defrost-A/C door is in defrost position, and heater-A/C-bi-level door is in A/C position. see scheme 7 Outside air will be cooled, dehumidified and heated as necessary, and then released out defroster outlets.

RECIRC Button

When RECIRC button is pressed, RECIRC LED will come on. RECIRC button will operate in all modes except DEFOG and FRONT DEFROST. Programmer will cause passenger compartment air to be recirculated through A/C-heater system. see scheme 7 Recirculation mode will operate for approximately 10 minutes and then deactivate. Recirculation mode will also be deactivated by manual mode changes and ignition cycles.

SENSORS

In-vehicle sensor, ambient (outside) air temperature sensor, and solar (sunload) sensors provide basic control inputs for the system. The microprocessor uses these sensor inputs to generate command signals for the programmer.

Ambient Temperature Sensor

Ambient temperature sensor is a thermistor located on radiator center support. A temperature memory feature is used during engine restart or in traffic to provide greater accuracy. Ambient temperature can be updated by pressing VENT button and RECIRC buttons at the same time.

In-Vehicle Temperature Sensor

In-vehicle temperature sensor is a thermistor located on top of instrument panel, above glove box. Temperature sensor fits inside a short horizontal tube, connected to an aspirator on the evaporator module. Inside air is drawn over thermistor, providing a constantly updated inside air temperature signal to A/C-heater control panel.

Sunload Sensor

Sunload sensors are located on left and right sides of instrument panel defroster grille. Sensors are light-sensitive photodiodes which respond to heat load of sunlight by changing resistance. Programmer compares solar sensor signals with in-vehicle temperature sensor to determine how much cooling is required to maintain selected temperature.

BLOWER CONTROL MODULE

Blower motor operation is controlled by a blower motor control module. The blower control module receives command signals from the programmer. Blower control module amplifies and applies the signals to the blower motor to vary its speed. Command signals are based on blower motor setting, mode selection, selected temperature, solar sensors, and difference between in-vehicle temperature and selected temperature.

A/C COMPRESSOR CONTROL RELAY

The compressor control relay cycles the compressor clutch on and off. With ignition on, battery voltage is applied to compressor clutch control relay. Powertrain Control Module (PCM) grounds compressor clutch control relay when A/C, DEFOG or FRONT DEFROST mode is selected and A/C pressure transducer and pressure cycling switches are closed.

A/C PRESSURE TRANSDUCER

A solid state A/C pressure transducer is mounted on discharge line from compressor and is used to monitor A/C system pressure. Pressure transducer sends a variable voltage signal to Powertrain Control Module (PCM). Higher A/C system pressure results in higher voltage output, and lower A/C system pressure results in lower voltage output. PCM uses voltage inputs to control compressor clutch operation and cooling fan low and high speed operations. PCM will disengage compressor clutch when A/C system pressure is greater than 430 psi (30.2 kg/cm 2 ) or less than 44 psi (3.1 kg/cm 2 ).

HIGH PRESSURE RELIEF VALVE

The high pressure relief valve is mounted on rear of A/C compressor. Valve acts as safety device. Valve opens to prevent system damage when refrigerant pressure exceeds approximately 461-599 psi (32-42 kg/cm 2 ), venting refrigerant to atmosphere. Any condition causing valve to open should be corrected. Refrigerant oil and refrigerant should be replaced as needed.

ORIFICE TUBE

The orifice tube meters liquid refrigerant flow into the evaporator. The orifice tube has filter screens on inlet and outlet sides. The tube has no moving parts and is not adjustable. If it is plugged or defective, it must be replaced.

BLOWER MOTOR CONTROL MODULE

Based on signal from programmer, blower control module supplies varying voltage (0-12 volts) to blower motor. Blower motor control module monitors a varying voltage signal (2-8 volts) from programmer. Control module will amplify voltage signal and apply to blower motor (4 volts is low speed and 12 volts is high speed). Control module output voltage is also monitored by programmer. In manual mode, there are 6 blower motor speeds that are fixed. In AUTO mode, blower speed is infinitely variable. Programmer varies blower motor speed according to inputs from inside and outside temperature sensors, solar sensors, engine coolant temperature sensor and vehicle speed sensor.

Intake (Fresh/Recirculated) Air Door

Vacuum actuator on left side of heater case controls fresh/recirculated air door. (Scheme 5) Solenoid on programmer controls vacuum supply to actuator.

Temperature Blend (Air Mix)

Air mix doors for driver and passenger sides of vehicle control airflow across heater core. Both doors are controlled by an electric actuator. Driver-side air mix door actuator is mounted on programmer and is serviceable separately from programmer. Passenger-side air mix door actuator is controlled by programmer. Programmer also monitors position of driver-side and passenger-side air mix doors.

Temperature of outlet air on passenger side can be controlled from knob on A/C-heater control panel or from knob on passenger door arm rest. Outlet air temperature at passenger side can be as much as 5°F (3°C) cooler or warmer than driver side. This is called a dual-zone system. If system is in OFF mode and either temperature control knob is turned, the system will automatically turn on to the AUTO mode.

Mode (Air Distribution)

Mode doors are controlled by vacuum actuators located on left side of heater case. (Scheme 5) Solenoids on programmer control vacuum supply to actuators.

Scheme 5

DRIVER-SIDE AIR MIX DOOR LINK

1. Lower the glove box door for access. Disconnect driver-side air mix link rod from air mix door threaded rod. (Scheme 6) Disconnect passenger-side air mix link rod from air mix door crank. Start engine. Set driver-side temperature control knob to maximum heating 90°F (32°C).
2. Set passenger-side temperature knob to full warm position. If outside temperature is greater than 90°F (32°C), disconnect in-vehicle temperature sensor connector. Allow at least 45 seconds for programmer to reach full hot position.
3. Gently pull driver-side air mix link rod toward programmer until door contacts stop. Connect driver side-air mix link rod to threaded rod (insert threaded rod into slot).
4. Gently pull passenger-side air mix link rod toward actuator until door contacts stop. Connect link rod to door crank. Cycle system between maximum heating and maximum cooling. Link rods should operate smoothly.

PASSENGER-SIDE AIR MIX DOOR LINK

Lower glove box door for access. Disconnect passenger-side air mix link rod from air mix door crank. (Scheme 6) Set driver-side temperature control knob to maximum heating (90°F). Allow at least 45 seconds for actuator link rod to move to full hot position. Move door crank to full hot position. Connect link rod to door crank.

Scheme 6

Preliminary Information

Perform following steps in sequence, with engine warm and idling. Ambient temperature must be at least 48°F (8°C). If engine has been running recently, system may delay operation of mode selection (air distribution) for about 20 seconds to purge moist air from system.

During this normal delay, system directs outlet air to floor ducts to prevent windshield fogging. System may also delay operation of mode selection if engine has not reached operating temperature. This normal delay prevents windshield frosting during cold weather.

1. Press OFF button. Outside temperature should be displayed. Blower should operate at lowest speed, and LED on OFF button should light.
2. Press UPPER button. Select manual fan (blower) speed control mode by pressing fan speed button up or down. LED on UPPER button should come on. Air delivery indicator and set temperature should be displayed. Temperature display should not blink. Blower motor should run, and corresponding number of fan segments should illuminate. Air should flow from dash panel outlets. Ensure outside temperature is displayed after 5 seconds. Compressor clutch will engage if ambient temperature is at least 48°F (8°C).
3. Press AUTO button once. Rotate temperature control knob to decrease temperature setting. Temperature display should decrease in one-degree decrements to 65°F (18°C). Once temperature setting reaches 65°F (18°C), next lowest available temperature setting is 60°F (16°C). Cool air should flow from dash panel outlets, and blower motor should run at high speed. Compressor clutch will engage if ambient temperature is at least 48°F (8°C). Ensure outside temperature is displayed after 5 seconds.
4. Rotate temperature control knob to increase temperature setting. Temperature display should increase in one-degree increments to 85°F (29°C). Once temperature setting reaches 85°F (29°C), next highest available temperature setting is 90°F (32°C). Airflow from dash panel outlets should become warmer, and blower motor should run at high speed (speed varies while temperature display changes). Compressor clutch should disengage. Ensure outside temperature is displayed after 5 seconds.
5. Press LOWER button. LED on LOWER button should come on. Selected temperature should be displayed for 5 seconds. Air should flow from floor outlets.
6. Press FRONT button. Response LEDs on FRONT (defrost) and A/C buttons should come on. Air should flow from defroster and floor outlets. Selected temperature should be displayed for 5 seconds. Compressor clutch will engage if ambient temperature is at least 48°F (8°C). Ensure outside temperature is displayed after 5 seconds.
7. Press DEFOG button. LED on DEFOG button should come on. Air should flow from defroster and floor outlets. Compressor clutch will engage if ambient temperature is at least 48°F (8°C). Ensure outside temperature is displayed after 5 seconds.
8. Press BI-LEV button. Air should flow from dash panel and floor outlets. Compressor clutch will engage if ambient temperature is at least 48°F (8°C). Ensure outside temperature is displayed after 5 seconds.
9. Press A/C button. LED on A/C button should come on. If control panel indicates DEFOG or DEFROST mode, A/C button cannot be turned off. If DTC 48 is set, LED on A/C button will not come on.
10. Press RECIRC button. LED on RECIRC button should come on in all modes except DEFOG and FRONT (defrost) modes. RECIRC function should time out after about 10 minutes.
11. Set temperature to 75°F (24°C). Close vehicle doors and windows. Press AUTO button. Temperature display should increase to 75°F (24°C). Passenger compartment temperature should be 75°F (24°C). Blower operation should decrease to minimum speed as passenger compartment temperature approaches 75°F (24°C). Ensure outside temperature is displayed after 5 seconds.
12. Adjust blower motor to lowest speed setting. Blower motor speed should decrease until one segment of fan bar is illuminated. Ensure LO is displayed.
13. Adjust blower motor to highest speed setting. Blower motor speed should increase until all segments of fan bar are illuminated. Ensure HI is displayed.
14. Turn ignition off for several seconds. Turn ignition switch to RUN position. Ensure outside temperature is displayed after 10 seconds. Displayed settings should be the same as those displayed before ignition was turned off.
15. Press PASS button. LED of PASS button on passenger-side climate control assembly should come on.
16. Set temperature to 65°F (18°C). Turn knob on passenger-side climate control assembly to full warm position. Discharge air on passenger's side of vehicle should be noticeably warmer than on driver's side of vehicle.
17. Set temperature to 85°F (29°C). Turn knob on passenger-side climate control assembly to full cold position. Discharge air on passenger's side of vehicle should be noticeably cooler than on driver's side of vehicle.
18. Turn system off. Turn knob on passenger-side climate control assembly in either direction. Ensure DUAL is displayed, and system enters dual zone mode.

Sunload Sensor Circuit Open or Shorted

1. Perform NORMAL SYSTEM RESPONSE TEST. Park vehicle in well lighted area. Connect Tech 1 scan tester and monitor suspect sunload sensor. Turn ignition switch to RUN position. Locate sunload sensors on top of instrument panel, and cover suspect sensor with cardboard. If sunload sensor counts increase from earlier value, go to next step. If counts do not increase, go to step 3).
2. Clear Diagnostic Trouble Codes (DTC). Turn ignition off and then on. If DTC 008 (passenger side) or DTC 015 (driver side) resets, go to next step. If DTC 008 or DTC 015 does not reset, inspect for loose, intermittent or poor connections.
3. Turn ignition off. Disconnect suspect sensor. Turn ignition on. Using voltmeter, measure voltage between sensor harness connector terminals "A" (DTC 008, Gray wire; DTC 015, Light Blue/Black wire) and "B" (Black/White wire). If voltage is not approximately 5 volts, go to next step. If voltage is approximately 5 volts, replace suspect sunload sensor.
4. If voltage is greater than 5 volts, repair short to battery voltage in Gray wire (DTC 008) or Light Blue/Black wire (DTC 015). If voltage is less than 5 volts, measure voltage between sensor harness connector terminal "A" (DTC 008, Gray wire; DTC 015, Light Blue/Black wire) and Data Link Connector (DLC) terminal No. 4 (Black wire). (Scheme 9) If voltage is approximately 5 volts, go to next step. If voltage is not approximately 5 volts, go to step 6).
5. If no other sensor DTC exists, repair open Black/White wire of suspect sensor. If other sensor DTCs exist, check for open Black/White wire. If wire is okay, replace programmer.
6. Using a voltmeter, backprobe between programmer connector terminal E15 (Gray wire - DTC 008) or terminal F10 (Light Blue/Black wire - DTC 015) and DLC terminal No. 4 (Black wire). If voltage is approximately 5 volts, repair open Gray wire or Light Blue/Black wire. If voltage is not approximately 5 volts, replace programmer.

Ambient Temperature Sensor Circuit Open Or Shorted

1. Perform NORMAL SYSTEM RESPONSE TEST. Turn ignition off. Disconnect ambient air temperature sensor connector, located at lower end of center radiator brace. Using ohmmeter, measure resistance across sensor terminals. See AMBIENT AIR TEMPERATURE SENSOR RESISTANCE table. If sensor resistance is as specified, go to next step. If resistance is not as specified, replace sensor.
2. Turn ignition on. Using voltmeter, measure voltage between sensor connector terminals "A" (Light Green/Black wire) and "B" (Black/White wire). If voltage is not about 5 volts, go to step 4). If voltage is about 5 volts, turn ignition off. Reconnect sensor harness connector. Turn ignition on, go to next step.
3. Using Tech 1 scan tester, clear Diagnostic Trouble Code (DTC) 010. Turn ignition off and then on. If DTC 010 does not reset, problem is intermittent. If DTC 010 resets, check for loose connection at harness connectors. If connections are okay, replace programmer.
4. If voltage is more than 5 volts, repair short to battery voltage in Light Green/Black wire between programmer and sensor. If voltage is less than 5 volts, measure voltage between sensor harness connector terminal "A" (Light Green/Black wire) and ground. If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 6).
5. If sensor DTCs are not present, check Black/White wire between sensor and programmer. Repair as necessary. If sensor DTCs are present, check for open Black/White wire between programmer, temperature sensors and solar sensors. If Black/White wire is okay, replace programmer.
6. DO NOT disconnect programmer connector. Using voltmeter, backprobe between programmer connector terminal F8 (Light Green/Black wire) and DLC terminal No. 4 (Black wire). If voltage is not about 5 volts, replace programmer. If voltage is about 5 volts, repair open Light Green/Black wire between sensor and programmer connector.

AMBIENT AIR TEMPERATURE SENSOR RESISTANCE

Inside Air Temperature Sensor Circuit Open Or Shorted

1. Perform NORMAL SYSTEM RESPONSE TEST. Turn ignition off. Disconnect in-vehicle temperature sensor harness connector. Using ohmmeter, measure resistance across sensor terminals. See IN-VEHICLE TEMPERATURE SENSOR RESISTANCE table. If resistance is not as specified, replace sensor. If resistance is as specified, go to next step.
2. Turn ignition on. Using voltmeter, measure voltage between sensor connector terminals "A" (Dark Green wire) and "B" (Black/White wire). If voltage is not about 5 volts, go to step 4). If voltage is about 5 volts, go to next step.
3. Turn ignition off. Reconnect sensor harness connector. Turn ignition on. Using Tech 1 scan tester, clear Diagnostic Trouble Code (DTC) 013. Turn ignition off and then on. If DTC 013 does not reset, problem is intermittent. If DTC 013 resets, check for loose connection at harness connectors. If connections are okay, replace programmer.
4. If voltage is more than 5 volts, repair short to battery voltage in Dark Green wire between programmer and sensor. If voltage is less than 5 volts, measure voltage between sensor connector terminal "A" (Dark Green wire) and DLC terminal No. 4 (Black wire). (Scheme 9) If voltage is not about 5 volts, go to step 6).
5. If voltage is about 5 volts, using Tech 1 scan tester, check for sensor DTCs. If DTCs are present, check for open Black/White wire between programmer, temperature sensors and solar sensors. If Black/White wire is okay, replace programmer. If DTCs are not present, repair open Black/White wire.
6. DO NOT disconnect programmer connector. Using voltmeter, backprobe between programmer connector terminal F7 (Dark Green wire) and DLC terminal No. 4 (Black wire). (Scheme 9) If voltage is not about 5 volts, replace programmer. If voltage is about 5 volts, repair open Dark Green wire between sensor and programmer connector.

IN-VEHICLE TEMPERATURE SENSOR RESISTANCE

Scheme 7

A/C-Heater Control-To-Programmer E & C Data Loss

1. Perform NORMAL SYSTEM RESPONSE TEST. Connect Tech 1 scan tester. Turn ignition switch to RUN position. Select E & C COMPONENT IDENTIFICATION. If scan tester does not display E & C BUS SHORTED TO GROUND or E & C BUS SHORTED TO BATTERY, go to next step. If scan tester displays E & C BUS SHORTED TO GROUND or E & C BUS SHORTED TO BATTERY, see appropriate ENGINE PERFORMANCE article in the ENGINE PERFORMANCE Section.
2. If any components are identified, go to next step. If no components are identified, see appropriate ENGINE PERFORMANCE article in the ENGINE PERFORMANCE Section.
3. If A/C-heater control panel is identified, go to step 4). If A/C-heater control panel is not identified, turn ignition off. Disconnect A/C-heater control panel. Check connector terminal No. 7 (Dark Green wire) and repair as necessary. If terminal contact is okay, remove terminal No. 7 from connector. Reconnect A/C-heater control panel. Turn ignition switch to RUN position. Measure DC voltage between terminal No. 7 and DLC terminal No. 4. (Scheme 7)and (Scheme 9). If battery voltage is not present, replace A/C-heater control panel. If battery voltage is present, repair open Dark Green wire.
4. Turn ignition off. Disconnect programmer. Disconnect A/C-heater control panel. Check continuity between programmer terminal E5 (Dark Green wire) and A/C-heater control panel terminal No. 7. If continuity is not present, repair open Dark Green wire.
5. If continuity is present, check programmer harness connector terminal E5 and A/C-heater control panel terminal No. 7 for good terminal contact. If terminal contact is okay, replace programmer.

Scheme 8

Scheme 9

Passenger Climate Control Panel Feedback Out Of Range

1. Perform NORMAL SYSTEM RESPONSE TEST. Turn ignition off. Disconnect passenger climate control panel. Measure resistance between passenger climate control panel pigtail connector terminals "A" (Dark Blue/White wire) and "B" (Black/White wire) while turning control knob to following settings: Full cold - 4800-5000 ohms. Mid-range - 2500-2700 ohms. Full hot - 96-104 ohms.
2. If resistance is not as specified, replace passenger climate control panel. If resistance is as specified, turn ignition switch to RUN position. Measure voltage between passenger climate control panel harness connector terminals "A" (Dark Blue/White wire) and "D" (Black wire). If voltage is not about 5 volts, go to step 4). If voltage is about 5 volts, go to next step.
3. Turn ignition off. Reconnect passenger climate control panel. Turn ignition switch to RUN position. Using Tech 1 scan tester, clear any DTC. Turn ignition off and then on. If DTC resets, check for good terminal contact at all connectors. If connectors are okay, replace programmer. If DTC does not reset, condition is intermittent.
4. If voltage is more than 5 volts, repair short to voltage in Dark Blue/White wire. If voltage is less than 5 volts, measure voltage between passenger control panel harness connector terminal "A" (Dark Blue/White wire) and DLC terminal No. 4 (Black wire). If voltage is not about 5 volts, go to next step. If voltage is about 5 volts, go to step 5).
5. Backprobe between programmer terminal F16 (Dark Blue/White wire) and DLC terminal No. 4 (Black wire). If voltage is about 5 volts, repair open Dark Blue/White wire. If voltage is not about 5 volts, replace programmer.
6. Measure voltage between passenger control panel connector terminal "B" (Black/White wire) and DLC terminal No. 4 (Black wire). If voltage is not present, go to next step. If voltage is present, repair short to voltage in Black/White wire.
7. Check continuity between passenger control panel connector terminal "B" (Black/White wire) and programmer terminal F6 (Black/White wire). If no continuity is present, repair open Black/White wire. If continuity is present, replace programmer.

Loss Of Serial Data (UART)

1. Perform NORMAL SYSTEM RESPONSE TEST. Turn ignition switch to RUN position. Connect Tech 1 scan tester to Data Link Connector (DLC). Try to establish communications on the serial data line at DLC terminal No. 9 (Tan wire). (Scheme 9) If Tech 1 scan tester does not communicate with Universally Asynchronous Receiving/Transmitting (UART) protocol system, see appropriate article in the ENGINE PERFORMANCE Section. If Tech 1 scan tester communicates, try to communicate with A/C system on the UART line (not the E & C line).
2. If Tech 1 scan tester does not communicate, go to next step. If Tech 1 scan tester communicates, use Tech 1 scan tester to clear Diagnostic Trouble Codes (DTC). Turn ignition off. Turn ignition switch to RUN position. If Diagnostic Trouble Code (DTC) 038 resets, replace programmer. If DTC 038 does not reset, system is okay.
3. Turn ignition off. Disconnect programmer connector. Remove terminals E10 and E11 (Tan wires) from programmer connector cavities. Reconnect programmer connector, leaving Tan wires disconnected. Turn ignition switch to RUN position.
4. Measure voltage, in turn, between programmer connector cavity terminals E10 and E11 (Tan wires) and DLC terminal No. 4 (Black wire). If voltage at each cavity is not approximately 5 volts, replace programmer. If voltage at each cavity is approximately 5 volts, check for poor connections at Tan wire terminals of programmer connector. If connections are okay, check for open Tan wires. If Tan wires are okay, replace programmer.

Loss Of Programmer Keep-Alive Memory (KAM)

1. Perform NORMAL SYSTEM RESPONSE TEST. If battery was recently disconnected or discharged, use Tech 1 scan tester to clear DTC. Turn ignition on and then off. If DTC 052 does not reset, system is okay at this time. If DTC 052 resets, go to next step.
2. Clear DTC 052. Inspect fuse 9C (10-amp) in instrument panel fuse block. If fuse is okay, go to next step. If fuse is blown, check for short to ground in Orange wire. Repair as necessary.
3. Turn ignition off. Disconnect programmer. Measure voltage between programmer harness connector terminals E1 (Black/White wire) and E13 (Orange wire). If battery voltage is present, inspect programmer harness connector for proper terminal contact. If no problems are found, replace programmer. If battery voltage is not present, repair open Black/White wire or Orange wire.

BLOWER MOTOR RUNS AT HIGH SPEED ONLY

1. Turn ignition off. Disconnect programmer electrical connector. Connect a fused jumper wire across blower motor connector terminals. Check resistance between ground and terminal F2 (Orange wire) of programmer connector. (Scheme 7)
2. If resistance is greater than 5 ohms, check for open circuit (including fuse) between terminal F2 (Orange wire) of programmer connector and blower motor. If resistance is less than 5 ohms, check for short to voltage in Gray/Black wire between programmer and blower control module.
3. If wire is okay, check for poor connection at terminal F2 (Orange wire) of programmer connector. If connection is okay, replace programmer.

BLOWER MOTOR DOES NOT RUN AT ANY SPEED

1. Disconnect blower motor connector. Turn ignition switch to RUN position. Press DEFOG button. Adjust blower motor to high speed setting. Check voltage at Purple wire terminal of blower motor connector.
2. If less than battery voltage is present, go to next step. If battery voltage is present, check voltage between blower motor connector terminals. If less than battery voltage is present, check for open Black wire between blower motor and ground. If battery voltage is present, check blower motor connector. If connector is okay, replace blower motor.
3. Check for open or short to ground in Purple wire between blower control module, blower motor and fuse. If Purple wire is okay, disconnect blower control module connectors. Check voltage at Red wire terminal of blower control module 2-pin connector.
4. If battery voltage is present, go to next step. If less than battery voltage is present, check fuse No. 3 in right underhood fuse block. If fuse is okay, check for open or short to ground in Red wire.
5. At blower control module, check voltage between Red wire terminal of 2-pin connector and Black wire terminal of 4-pin connector. If less than battery voltage is present, check for open Black wire. If battery voltage is present, check voltage at Gray/Black wire terminal of 4-pin connector.
6. If less than 6 volts is present, go to next step. If 6-8 volts is present, check for poor connection at blower control module connectors. If connections are okay, replace blower control module.
7. Check Gray/Black wire for short to ground or open (including poor connection at programmer). If Gray/Black wire is okay, replace programmer.