HVAC Systems - Manual Chevrolet Chevy Express H2500

Intermittents

Intermittent faulty electrical connections or wiring may be the cause of intermittent conditions. Check for loose, bent or corroded terminals and terminal tension. Check for cut, bare or pinched wiring. Simulate the condition that is potentially causing the intermittent connection, either by wiggling the connections or the wiring, test driving or performing other operations while observing scan tool, DVOM or other testing equipment. See TESTING FOR INTERMITTENT AND POOR CONNECTIONS .

Fastener Tightening Specifications

Fastener Tightening Specifications

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Scan Tool Data List

Use the Scan Tool Data Display Values and Definitions Information in order to assist in diagnosing the Powertrain Control Module (PCM) problems. Compare the vehicles actual scan tool data with the typical data display value table information. Use the data information in order to aid in understanding the nature of the problem when the vehicle does not match with the typical data display values.

The scan tool data values were taken from a known good vehicle under the following conditions

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1. The ignition switch is in the ON position.
2. The engine is running at idle.
3. The vehicle is in PARK.
4. The doors are closed.
5. The windows are closed.
6. The A/C is ON.
7. The ambient air temperatures are at 22-27° C (70-80°F).

Scan Tool Data Definitions

The HVAC Scan Tool Data Definitions contains a brief description of all HVAC related parameters available on the scan tool. The list is in alphabetical order. A given parameter may appear in any one of the data lists. In some cases, the parameter may appear more than once or in more than one data list in order to group certain related parameters together.

PCM, - A/C Clutch Feedback Signal: The scan tool displays Relay Off or Relay On. Represents the status of the relay.

PCM - A/C Compressor Cycling Switch: The scan tool displays Low Pressure or Normal. This parameter displays the state of the A/C compressor cycling switch. The A/C compressor cycling switch is a normally closed switch.

PCM - A/C High Pressure Recirculation

Switch: The scan tool displays High Pressure or Normal. Represents the status of the high pressure recirculation switch.

PCM - A/C Relay Command : The scan tool displays On or Off. This parameter displays the PCM commanded state of the A/C compressor clutch relay. When the scan tool displays ON, the A/C compressor clutch should be engaged.

PCM - A/C Request : The scan tool displays Yes or No. The A/C Request displays the state of the A/C request input circuit from the heating, ventilation control module (PCM) uses the A/C request signal in order to determine whether the A/C compressor operation is being requested.

PCM

ECT Sensor : The scan tool displays a range of 39 to +140°C (38 to +284°F). The powertrain control module (PCM) applies 5.0 volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as the engine temperature changes. When the sensor is cold, internal resistance is high, the PCM senses a high signal voltage and interprets the voltage as a cold engine. As the sensor warms, internal resistance decreases, the voltage signal decreases, and the PCM interprets the lower voltage as a warm engine.

Important : Review the system operation in order to familiarize yourself with the system functions. Refer to

1. «Air Delivery Description and Operation»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__air-delivery-description-and-operation)
2. «Air Temperature Description and Operation»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__air-temperature-description-and-operation)

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the HVAC System.
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
3. Verify the A/C compressor clutch turns freely and is not seized.
4. The A/C compressor will not operate in cold outside air temperatures. Refer to «Air Temperature Description and Operation»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__air-temperature-description-and-operation) .
5. The following conditions may cause window fogging: Wet carpet or mats High humidity Interior water leak Blocked A/C evaporator drain tube Maximum passenger capacity Blocked body pressure relief valves
6. Inspect the air distribution system for causes of reduced air flow: Obstructed or dirty passenger compartment air filter, if equipped Blocked or damaged air inlet or outlet vents

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «HVAC Compressor Clutch Does Not Engage»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__hvac-compressor-clutch-does-not-engage)
2. «HVAC Compressor Clutch Does Not Disengage»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual)
3. «Blower Motor Always On»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__blower-motor-always-on)
4. «Blower Motor Inoperative»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__blower-motor-inoperative)
5. «Blower Motor Malfunction»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual)
6. «Blower Motor Always On - Auxiliary (Passenger Van w/Aux)»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__blower-motor-always-on-auxiliary) or «Blower Motor Always On - Auxiliary (Aux Heat Only or Cargo Van w/Aux)»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual)
7. «Blower Motor Inoperative - Auxiliary»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual)
8. «Blower Motor Malfunction - Auxiliary»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__blower-motor-malfunction-auxiliary)
9. «Too Hot in Vehicle»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__too-hot-in-vehicle)
10. «Too Cold in Vehicle»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__too-cold-in-vehicle)
11. «Too Hot in Vehicle - Auxiliary (Passenger Van w/Aux)»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__too-hot-in-vehicle-auxiliary) or «Too Hot in Vehicle - Auxiliary (Cargo Van w/Aux)»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__too-hot-in-vehicle-auxiliary) or «Too Hot in Vehicle - Auxiliary (Cargo Van w/Aux Rear Heater)»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__too-hot-in-vehicle-auxiliary) .
12. «Too Cold in Vehicle - Auxiliary (Passenger Van w/Aux)»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__too-cold-in-vehicle-auxiliary) or «Too Cold in Vehicle - Auxiliary (Cargo Van w/Aux)»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__too-cold-in-vehicle-auxiliary) or «Too Cold in Vehicle - Auxiliary (Cargo Van w/Aux Rear Heater)»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual__too-cold-in-vehicle-auxiliary) .
13. «Air Delivery Improper»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual)
14. «Air Delivery Improper - Auxiliary (Passenger Van w/Aux)»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual) or «Air Delivery Improper - Auxiliary (Cargo Van w/Aux)»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual) .
15. «Vacuum Control System Diagnostic»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#hvac-systems-manual)
16. «LEAK TESTING»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning)
17. «DEFROSTING INSUFFICIENT»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning__defrosting-insufficient)
18. «NOISE DIAGNOSIS - BLOWER MOTOR»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning)
19. «NOISE DIAGNOSIS - AIR CONDITIONING (A/C) SYSTEM»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning)
20. «NOISE DIAGNOSIS - HVAC MODULE»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning)
21. «ODOR DIAGNOSIS»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning)

HVAC Compressor Clutch Does Not Engage

Test Description

The numbers below refer to the step numbers on the diagnostic table.

2. The A/C compressor relay output is disabled if engine coolant temperature is above 121°C (250°F).

5. The HVAC control assembly is inoperative when the assembly does not respond to any operator control requests.

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Blower Motor Always On

Test Description

The numbers below refer to the step numbers on the diagnostic table.

2. This step checks for continuous operation of the blower motor.

3. This step tests for a short to voltage in the mode switch output and the LO, M1, M2, and HI blower motor control circuits. It is easiest to perform this step by disconnecting the blower motor resistor assembly connector, and probing each speed control circuit with a test lamp connected to a known good ground.

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Blower Motor Inoperative

Test Description

The numbers below refer to the step numbers on the diagnostic table.

2. This step tests for blower motor operation in any speed setting.

3. This step tests for voltage at the blower motor.

4. This step tests for a possible open in the blower motor resistor assembly or blower motor ground circuit.

5. This step tests for output voltage from the blower motor switch.

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Blower Motor Always On - Auxiliary (Passenger Van w/Aux)

Test Description

The numbers below refer to the step numbers on the diagnostic table.

15. The auxiliary blower motor switch control circuit is the circuit that enables the rear auxiliary HVAC control assembly when the front auxiliary blower motor switch is placed in the rear control position.

16. The auxiliary blower motor switch control circuit is the circuit that enables the rear auxiliary HVAC control assembly when the front auxiliary blower motor switch is placed in the rear control position.

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Blower Motor Malfunction - Auxiliary

Test Description

The numbers below refer to the step numbers on the diagnostic table.

7. Test the circuit that did not illuminate the test lamp in Step 6.

10. The control circuit of the auxiliary blower motor relay is the circuit which provides the ground path for the relay coil through the auxiliary blower motor switch esi.

14. Test the blower motor control circuit that corresponds with the inoperative blower motor speed.

15. The auxiliary blower motor switch control circuit is the circuit that enables the rear auxiliary HVAC control assembly when the front auxiliary blower motor switch is placed in the rear control position.

16. The auxiliary blower motor switch control circuit is the circuit that enables the rear auxiliary HVAC control assembly when the front auxiliary blower motor switch is placed in the rear control position.

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Too Hot in Vehicle

Test Description

The numbers below refer to the step numbers on the diagnostic table.

7. The specified values are from the A/C System Performance Test.

13. The voltage will vary between 0-12 volts during normal operation. The HVAC control assembly connector must be connected during this step.

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Too Cold in Vehicle

Test Description

The numbers below refer to the step numbers on the diagnostic table.

5. This checks for proper cooling system operation.

12. The voltage will vary between 0-12 volts during normal operation. The HVAC control assembly connector must be connected during this step.

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Too Hot in Vehicle - Auxiliary (Passenger Van w/Aux)

Test Description

The numbers below refer to the step numbers on the diagnostic table.

5. The specified values are from the A/C System Performance Test.

9. This check for proper air temperature actuator movement.

10. The voltage will vary between 0-12 volts during normal operation. The front auxiliary HVAC control assembly connector must be connected during this step. This checks for proper operation of the air temperature actuator door control circuit and the front auxiliary HVAC control assembly.

13. The voltage will vary between 0-12 volts during normal operation. The front auxiliary HVAC control assembly connector must be connected during this step. This checks for proper operation of the air temperature actuator door control circuit and the front auxiliary HVAC control assembly.

14. The auxiliary blower motor switch control circuit should not have continuity to ground when the front auxiliary HVAC control assembly is in any position except REAR CNTL.

16. The voltage will vary between 0-12 volts during normal operation. The rear auxiliary HVAC control assembly connector must be connected during this step. This checks for proper operation of the air temperature actuator door control circuit and the rear auxiliary HVAC control assembly.

20. This step checks the complete auxiliary air temperature door control circuit, from the front HVAC control assembly, through the auxiliary HVAC control processor to the auxiliary air temperature actuator.

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Too Hot in Vehicle - Auxiliary (Cargo Van w/Aux)

Test Description

The numbers below refer to the step numbers on the diagnostic table.

6. The specified values are from the A/C System Performance Test.

12. The voltage will vary between 0-12 volts during normal operation. The front auxiliary HVAC control assembly connector must be connected during this step. This checks for proper operation of the air temperature actuator door control circuit and the front auxiliary HVAC control assembly.

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Too Hot in Vehicle - Auxiliary (Cargo Van w/Aux Rear Heater)

Test Description

The numbers below refer to the step numbers on the diagnostic table.

5. The specified values are from the A/C System Performance Test. This step links to Too Hot in Vehicle because system shows no sign of concern with auxiliary heater.

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Too Cold in Vehicle - Auxiliary (Passenger Van w/Aux)

Test Description

The numbers below refer to the step numbers on the diagnostic table.

4. This checks for proper cooling system operation.

9. This checks for proper air temperature actuator movement.

10. The voltage will vary between 0-12 volts during normal operation. The front auxiliary HVAC control assembly connector must be connected during this step. This checks for proper operation of the air temperature actuator door control circuit and the front auxiliary HVAC control assembly.

13. The voltage will vary between 0-12 volts during normal operation. The front auxiliary HVAC control assembly connector must be connected during this step. This checks for proper operation of the air temperature actuator door control circuit and the front auxiliary HVAC control assembly.

14. The auxiliary blower motor switch control circuit should not have continuity to ground when front auxiliary HVAC control assembly is in any position except REAR CNTL.

16. The voltage will vary between 0-12 volts during normal operation. The rear auxiliary HVAC control assembly connector must be connected during this step. This checks for proper operation of the air temperature actuator door control circuit and the rear auxiliary HVAC control assembly.

20. This step checks complete auxiliary air temperature door control circuit from the front HVAC control assembly to the auxiliary HVAC control processor to the auxiliary air temperature actuator.

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Too Cold in Vehicle - Auxiliary (Cargo Van w/Aux)

Test Description

The numbers below refer to the step numbers on the diagnostic table.

4. This checks for proper cooling system operation.

11. The voltage will vary between 0-12 volts during normal operation. The front auxiliary HVAC control assembly connector must be connected during this step. This checks for proper operation of the air temperature actuator door control circuit and the front auxiliary HVAC control assembly.

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Too Cold in Vehicle - Auxiliary (Cargo Van w/Aux Rear Heater)

Test Description

The numbers below refer to the step numbers on the diagnostic table.

4. This checks for proper cooling system operation. This step links to Too Cold in Vehicle because system shows no sign of concern with auxiliary heater.

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1. Remove the I/P cluster trim plate. Refer to Trim Plate Bezel Replacement - Instrument Panel (I/P) Cluster in Instrument Panel, Gages and Console .
2. Remove the retaining screw from the HVAC control assembly.
3. Pivot the HVAC control assembly to disengage the locking tab on the right side.
4. Disconnect the electrical connectors.
5. Disconnect the vacuum connector.
6. Remove the HVAC control assembly.

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1. Connect the vacuum connector.
2. Connect the electrical connectors.
3. Install the HVAC control assembly. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
4. Install the retaining screw to the HVAC control assembly. Tighten Tighten the screw to 2 N.m (18 lb in).
5. Install the I/P cluster trim plate. Refer to Trim Plate Bezel Replacement - Instrument Panel (I/P) Cluster in Instrument Panel, Gages and Console .

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1. Remove the passenger side knee bolster. Refer to Knee Bolster Replacement - Right in Instrument Panel, Gages, and Console .
2. Disconnect the air temperature actuator electrical connector.
3. Remove the air temperature actuator retaining screws.
4. Remove the air temperature actuator (1) from the heater assembly (2).

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1. Install the air temperature actuator (1) to the heater assembly (2). CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the air temperature actuator retaining screws. Tighten Tighten the screws to 1.9 N.m (17 lb in).
3. Connect the air temperature actuator electrical connector.
4. Install the passenger side knee bolster. Refer to Knee Bolster Replacement - Right in Instrument Panel, Gages, and Console .

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1. Remove the I/P carrier. Refer to Instrument Panel (I/P) Carrier Replacement in Instrument Panel, Gages, and Console .
2. Disconnect the vacuum hose (1) from the defrost actuator (2).
3. Depress the clip and remove the defrost actuator (2) from the heater assembly.

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1. Install the defrost actuator (2) to the heater assembly.
2. Connect the vacuum hose (1) to the defrost actuator (2).
3. Install the I/P carrier. Refer to Instrument Panel (I/P) Carrier Replacement in Instrument Panel, Gages, and Console .

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1. Remove the IP carrier. Refer to Instrument Panel (I/P) Carrier Replacement in Instrument Panel Gages and Console .
2. Release the tabs from the upper mode actuator.
3. Remove the upper mode actuator.

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1. Install the upper mode actuator.
2. Press upper mode actuator on until you hear tabs engage.
3. Install the IP carrier. Refer to Instrument Panel (I/P) Carrier Replacement in Instrument Panel Gages and Console .

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1. Remove the IP carrier. Refer to Instrument Panel (I/P) Carrier Replacement in Instrument Panel Gages and Console .
2. Release the tabs from the lower mode actuator.
3. Remove the lower mode actuator.

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1. Install the lower mode actuator.
2. Press lower mode actuator on until you hear tabs engage.
3. Install the IP carrier. Refer to Instrument Panel (I/P) Carrier Replacement in Instrument Panel Gages and Console .

Recirculation Actuator Replacement

Tools Required

J-39400-A Electronic Leak Detector

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1. Recover the refrigerant from the A/C system. Refer to «REFRIGERANT RECOVERY AND RECHARGING»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Disconnect the low pressure sensor electrical connector.
3. Disconnect the blower motor electrical connector.
4. Disconnect the blower motor resistor assembly electrical connector.
5. Remove the evaporator outlet hose retaining nuts (4,5).
6. Remove the retaining nut (3) from the evaporator inlet tube (5).
7. Remove the evaporator inlet tube from the evaporator.
8. Remove the sealing washers.
9. Remove the screws (2) from the evaporator and blower module assembly.
10. Remove the evaporator and blower module assembly front cover (3).
11. Remove the recirculation door actuator (7) and the linkage.

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1. Install the recirculation door actuator (7) and the linkage.
2. Install the evaporator and blower module assembly cover (3). CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
3. Install the screws. Tighten Tighten the screws to 1.9 N.m (17 lb in).
4. Install new sealing washers to the evaporator inlet and outlet tubes. Refer to «SEALING WASHER REPLACEMENT»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning) .
5. Install the evaporator inlet tube (4) to the evaporator (5).
6. Install the evaporator inlet tube retaining nut (3). Tighten Tighten the nut to 16 N.m (12 lb ft).
7. Install the evaporator outlet hose and retaining nuts (4,5). Tighten Tighten the nut to 18 N.m (13 lb ft).
8. Connect the low pressure sensor electrical connector.
9. Connect the blower motor electrical connector.
10. Connect the blower motor resistor assembly electrical connector.
11. Evacuate and recharge the A/C system. Refer to «REFRIGERANT RECOVERY AND RECHARGING»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
12. Leak test the fittings of the repaired or replaced component. Refer to J-39400-A .

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1. Disconnect the vacuum hose from the vacuum tank.
2. Remove the screws (1) from the vacuum tank retainers.
3. Remove the vacuum tank (3).

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1. Install the vacuum tank (3). CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the screws (1) to the vacuum tank retainers. Tighten Tighten the screws to 6 N.m (53 lb in).
3. Connect the vacuum hose.

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1. Remove the front control switch bezel (4) from the headliner.
2. Remove the front control switch (3) by unsnapping the retainers from the headliner.
3. Disconnect the electrical connector.

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1. Connect the electrical connector.
2. Install the front control switch (3) by snapping the retainers to the headliner.
3. Install the front control switch bezel (4) to the headliner.

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1. Remove the HVAC control assembly bezel (3) from the headliner (2).
2. Lower the front headliner to access the rear of the HVAC control assembly (1).
3. Disconnect the electrical connectors.
4. Remove the HVAC control assembly from the front headliner.

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1. Install the HVAC control assembly (1) in the front headliner and attach the bezel (3).
2. Connect the electrical connectors.
3. Install the front headliner (2).

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1. Lower the front headliner to access the HVAC control processor.
2. Remove the HVAC control processor from the roof panel.
3. Remove the HVAC control processor access cover (3).
4. Remove the HVAC control processor (2) from the HVAC processor case (1).

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1. Install the HVAC control processor (2) to the HVAC processor case (1).
2. Install the HVAC control processor access cover (3).
3. Install the HVAC control processor to the roof panel.
4. Install the front headliner.

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1. Remove the instrument cluster trim plate. Refer to Trim Plate Bezel Replacement - Instrument Panel (I/P) Cluster in Instrument Panel, Gages and Console .
2. Disconnect the electrical connector from the switch.
3. Remove the switch from the bezel by releasing the tabs on the side of the switch.

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1. Install the switch into the bezel by snapping the switch into place.
2. Connect the electrical connector to the switch.
3. Install the instrument cluster trim plate. Refer to Trim Plate Bezel Replacement - Instrument Panel (I/P) Cluster in Instrument Panel, Gages and Console .

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1. Remove the left rear quarter trim panel. Refer to Trim Panel Replacement - Left Body Side in Interior Trim .
2. Disconnect the electrical connector from the air temperature actuator.
3. Remove the retaining screws from the air temperature actuator.
4. Remove the air temperature actuator.

Scheme 298

1. Install the air temperature actuator. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the retaining screws to the air temperature actuator. Tighten Tighten the screws to 1.9 N.m (17 lb in).
3. Connect the air temperature electrical connector to the actuator.
4. Install the left rear quarter trim panel. Refer to Trim Panel Replacement - Left Body Side in Interior Trim .

Scheme 299

1. Remove the heater assembly. Refer to «HEATER ASSEMBLY REPLACEMENT»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Remove the retaining screws from the auxiliary mode actuator.
3. Remove the auxiliary mode actuator.

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1. Install the auxiliary mode actuator. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the retaining screws to the auxiliary mode actuator. Tighten Tighten the screws to 1.9 N.m (17 lb in).
3. Install the heater assembly. Refer to «HEATER ASSEMBLY REPLACEMENT»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning) .

Air Delivery Description and Operation

The air delivery description and operation is divided into 6 areas

1. HVAC Control Components
2. Air Speed
3. Auxiliary Air Speed
4. Air Distribution
5. Auxiliary Air Delivery
6. Recirculation Operation

HVAC Control Assembly

The HVAC control assembly is a non-class 2 device that interfaces between the operator and the HVAC system to maintain air temperature and distribution settings. The ignition 3 voltage circuit provides power to the control assembly. Two integrated potentiometers control air temperature door position and blower motor speed. The integrated vacuum system controls the mode door position. The control assembly supports the following features

Scheme 301

Auxiliary HVAC Control Processor

The auxiliary HVAC control processor controls all outputs for the auxiliary HVAC system. The auxiliary HVAC control processor receives inputs from the front and rear auxiliary HVAC control assemblies. The auxiliary HVAC control processor does not utilizer Class 2 communications. If the auxiliary HVAC control processor receives a 12 volt varied voltage input for an auxiliary air temperature actuator change request. Then the auxiliary HVAC control processor creates a 12 volt varied output for control of the auxiliary air temperature actuator.

Auxiliary Mode Actuator

The auxiliary mode actuator is a 3 wire bi-directional electric motor. Ignition 3 voltage, ground and control circuits enable the actuator to operate. The control circuit uses a 0-12 volt linear-ramped signal to command the actuator movement. The 0 and 12 volt control values represent the opposite limits of the actuator range of motion. The values in between 0 and 12 volts correspond to the positions between the limits. When the HVAC control assembly sets a commanded, or targeted, value, the control signal is set to a value between 0-12 volts. The actuator shaft rotates until the commanded position is reached. The module will maintain the control value until a new commanded value is needed.

Air Speed

The HVAC control assembly applies voltage to the blower motor control circuit that corresponds to the selected blower speed. The resistors and the blower motor are in a series circuit. The following list represents the number of resistors in series with the blower motor per particular speed request

1. Low speed - 3 resistors
2. Medium 1 speed - 2 resistors
3. Medium 2 speed - 1 resistor

When the operator requests High speed, the HVAC control assembly applies voltage to the blower motor relay through the high blower motor control circuit. The voltage energizes the blower motor relay, connecting the blower motor to battery positive voltage.

Auxiliary Air Speed

The auxiliary HVAC control assembly applies voltage to the auxiliary blower motor control circuit that corresponds to the selected blower speed. The resistors and the blower motor are in a series circuit. The following list represents the number of resistors in series with the blower motor per particular speed request

1. Low speed - 2 resistors
2. Medium speed - 1 resistor

When the operator requests High speed, the HVAC control assembly applies voltage to the blower motor relay through the auxiliary high blower motor control circuit. The voltage energizes the blower motor relay, connecting the blower motor to battery positive voltage.

Mode Switch

The mode switch is a rotary vacuum valve that directly applies vacuum to the appropriate vacuum actuator. Use the mode switch to change the air delivery mode in the vehicle.

MAX A/C-If Equipped

When the operator selects MAX A/C, the mode actuator has vacuum applied to it through the Brown vacuum line, making the vent door open. The recirculation actuator has vacuum applied to it through the Orange vacuum line, making the recirculation door close and allowing air to be recirculated. A/C is forced ON.

A/C-If Equipped

When the operator selects A/C, the mode actuator has vacuum applied to it through the Brown vacuum line, making the vent door open. A/C is forced ON.

BI-Level Mode

When the operator selects Bi-Level, the following occurs

1. The mode actuator is in neutral position.
2. The defrost actuator has vacuum applied to it through the Yellow vacuum line.
3. The defrost actuator closes the defrost door, thus opening the heater door though mechanical linkage.
4. Vacuum is bled off the mode actuator and the vent door is held stationary in the half open position.

Vent Mode

When the operator selects VENT, the mode actuator has vacuum applied to it through the Yellow vacuum line, making the vent door open.

Floor Mode

When the operator selects FLOOR, the defrost actuator has vacuum applied to it through the Pink vacuum line, pulling the defrost door closed and opening the heater door through mechanical linkage.

Mix-Blend Mode

When the operator selects Mix-Blend, the following occurs

1. Vacuum is bled off the defrost actuator, holding the defrost door stationary in the half-open position. The heater door is also held stationary in the half-open position through mechanical linkage.
2. A/C is forced ON.
3. Recirculation is not available.

Defrost Mode

When the operator selects Defrost, the following occurs

1. The defrost actuator has vacuum applied to it through the Blue vacuum line, pushing the defrost door open and closing the heater door through mechanical linkage.
2. A/C is forced ON.
3. Recirculation is not available.

Auxiliary Air Distribution

The HVAC control assembly controls the mode actuator in order to distribute airflow to a desired outlet. When the mode door is moved to the defrost position, the A/C compressor clutch engages and the recirculation actuator will be moved to the outside air position. Regardless of the mode setting, a small amount of air will be diverted to the defrost ducts to reduce windshield fogging. When VENT is selected, the following will occur

1. The mode actuator will be moved to the panel position.
2. The recirculation actuator will be placed in the outside air position.
3. The A/C compressor will be commanded off.

Recirculation Operation

When the operator selects Recirculation, the HVAC control assembly connects the recirculation door vacuum actuator to the vacuum source. The recirculation actuator retracts, closing the recirculation blower motor in either the ON or OFF position. Recirculation will continue until either outside air is selected or the next ignition cycle. Recirculation is not available in Defrost and Mix-Blend mode.

Air Temperature Description and Operation

The air temperature controls are divided into five areas.

1. HVAC Control Components
2. Heating and A/C Operation
3. Auxiliary Heating and A/C Operation
4. Engine Coolant
5. A/C Cycle

The HVAC control assembly is a non-Class 2 device that interfaces between the operator and the HVAC system to maintain air temperature and distribution settings. The ignition 3 voltage circuits provide power to the control assembly. Two integrated potentiometers control air temperature door position and blower motor speed. The integrated vacuum system controls the mode door position. The control assembly supports the following features

Scheme 302

The auxiliary HVAC control processor controls all outputs for the auxiliary HVAC system. The auxiliary HVAC control processor receives inputs from the front and rear auxiliary HVAC control assemblies. The auxiliary HVAC control processor does not utilize Class 2 communications.

If the auxiliary HVAC control processor receives a 12 volt varied voltage input for an auxiliary air temperature actuator change request. Then the auxiliary HVAC control processor creates a 12 volt varied output for control of the auxiliary air temperature actuator.

Air Temperature Actuator

The air temperature actuator and auxiliary air temperature actuator are a 3 wire bi-directional electric motor. Ignition 3 voltage, ground and control circuits enable the actuator to operate. The control circuit uses a 0-12 volt linear-ramped signal to command the actuator movement. The 0 and 12 volt control values represent the opposite limits of the actuator range of motion. The values in between 0 and 12 volts correspond to the positions between the limits.

When the HVAC control assembly sets a commanded, or targeted, value, the control signal is set to a value between 0-12 volts. The actuator shaft rotates until the commanded position is reached. The module will maintain the control value until a new commanded value is needed.

A/C Pressure Switches

The A/C system is protected by two A/C pressure switches.

1. A/C low pressure switch
2. A/C high pressure switch

The A/C high pressure switch interrupts the A/C request signal when the A/C line pressure is more than a predetermined value. The A/C line pressure is more than a predetermined value. The A/C low pressure switch interrupts the A/C low pressure switch signal when the A/C line pressure switch signal when the A/C line pressure is less than or more than a predetermined value. When the powertrain control module (PCM) stops receiving the required signals, the A/C compressor clutch relay control circuit is no longer grounded, disengaging the A/C compressor clutch. The A/C compressor clutch is disengaged under the following conditions

1. A/C low pressure switch is less than 124 kPa (18 psi).
2. A/C low pressure switch is more than 338 kPa (49 psi).
3. A/C high pressure switch is more than 2896 kPa (420 psi).

Bypass Valves

The bypass valves included in the air temperature system are

1. Coolant Bypass Valve
2. Hot Water Bypass Valve

The bypass valve is a normally open valve, which closes when vacuum is applied to the valve. When the MAX A/C mode is selected, vacuum from the HVAC control assembly is applied to the bypass valve. The vacuum must be strong enough to overcome the tension of the valve's internal return spring in order to close the bypass valve. The return spring forces the valve to return to the open position, when any of the other HVAC modes are selected. In the closed position, the flow of coolant to the heater core is bypassed, allowing maximum cooling to the passenger compartment.

Heating and A/C Operation

The purpose of the heating and A/C system is to provide heated and cooled air to the interior of the vehicle. The A/C system will also remove humidity from the interior and reduce windshield fogging. The vehicle operator can determine the passenger compartment temperature by adjusting the air temperature switch. Regardless of the temperature setting, the following can effect the rate that the HVAC system can achieve the desired temperature

1. Recirculation
2. Difference between inside and desired temperature
3. Difference between ambient and desired temperature
4. Blower motor speed setting
5. Mode setting
6. Auxiliary HVAC settings

The A/C system can be engaged by placing the mode switch in one of the following positions

1. Max A/C
2. A/C
3. Bi-Level
4. Blend
5. Defrost

The A/C system can operate regardless of the temperature setting. Regardless of the selected A/C mode setting, a request is sent to the PCM to turn on the A/C compressor clutch.

The following conditions must be met in order for the PCM to turn on the compressor clutch

1. Ambient air temperature is greater than 3°C (38°F)
2. Engine coolant temperature (ECT) is less than 123°C (253°F)
3. Engine speed is less than 5000 RPM
4. The A/C compressor cycling switch pressure is between 124-388 kPa (18-49 psi)
5. The A/C high pressure cutout switch is less than 2896 kPa (420 psi)

Once engaged, the compressor clutch will be disengaged for the following conditions

1. Throttle position is 100%
2. The A/C compressor cycling switch pressure is less than 124 kPa (18 psi) or more than 338 kPa (49 psi)
3. The A/C high pressure cutout switch is more than 2896 kPa (420 psi)
4. Engine coolant temperature (ECT) is more than 123°C (253°F)
5. Engine speed is more than 5000 RPM
6. Transmission shift
7. PCM detects excessive torque load
8. PCM detects insufficient idle quality
9. PCM detects a hard launch condition

When the compressor clutch disengages, the compressor clutch diode protects the electrical system from a voltage spike.

Heater Mode - Auxiliary Heater without A/C

The auxiliary blower motor recycles air from the vehicle's interior. The vehicle operator can determine the intensity of the auxiliary heater by placing the auxiliary blower motor in one of the following positions

1. Low
2. Med
3. High

Since there is no temperature switch, the temperature is controlled by the speed of the auxiliary blower motor. The auxiliary blower motor will only operate when the ignition is in the RUN position, and the auxiliary blower motor switch is in any position other than OFF.

Heater Mode - Front Auxiliary HVAC Control Assembly Only

The auxiliary temperature switch in the front auxiliary HVAC control assembly allows the vehicle operator to adjust the temperature in the rear of the vehicle. Power is provided to both the front auxiliary HVAC control assembly and the auxiliary air temperature actuator from the IP fuse block on the ignition 3 voltage circuit.

Voltage delivered to the front auxiliary HVAC control assembly on the ignition 3 voltage circuit is sent to a variable resistor. Based on the placement of the temperature switch, a varied voltage is sent to the auxiliary air temperature actuator on the auxiliary air temperature door control circuit. The auxiliary air temperature actuator positions the temperature door to divert the appropriate amount of air past the heater core in order to achieve the desired temperature.

Heater Mode - Front Auxiliary HVAC Control Assembly with Rear Auxiliary HVAC Control Assembly

The auxiliary temperature switch in the front auxiliary HVAC control assembly allows the vehicle operator to adjust the temperature in the rear of the vehicle. Power is provided to both the front auxiliary air temperature actuator from the IP fuse block on the ignition 3 voltage circuit.

Voltage delivered to the front auxiliary HVAC control assembly on the ignition 3 voltage circuit is sent to a varied resistor. Based on the placement of the temperature switch, a varied voltage is sent to the auxiliary air temperature actuator on the auxiliary air temperature door control circuit, and auxiliary HVAC control processor. The auxiliary air temperature actuator positions the temperature door to divert the appropriate amount of air past the heater core in order to achieve the desired temperature

Heater Mode - Rear Auxiliary HVAC Control Assembly

The auxiliary temperature switch in the rear auxiliary HVAC control assembly allows the rear seat passengers to adjust the temperature in the rear of the vehicle. Power is provided to the rear auxiliary HVAC control assembly, auxiliary HVAC control processor and the auxiliary air temperature actuator from the IP fuse block on the ignition 3 voltage circuit. To activate the rear auxiliary HVAC control assembly, the front auxiliary HVAC control assembly must be placed in the REAR CNTL position. Ignition 3 voltage is sent to the auxiliary HVAC control processor.

When the switch is placed in the REAR CNTL position, the voltage is grounded through the auxiliary blower motor switch control, front auxiliary HVAC control assembly and the ground circuit to allow the rear auxiliary HVAC control assembly to operate the auxiliary temperature actuator. Voltage delivered to the rear auxiliary HVAC control assembly on the ignition 3 voltage circuit is sent to a variable resistor. Based on the placement of the temperature switch, a varied voltage is sent to the auxiliary air temperature actuator on the auxiliary air temperature door control circuit, and auxiliary HVAC control processor. The auxiliary air temperature actuator positions the temperature door to divert the appropriate amount of air past the heater core in order to achieve the desired temperature.

A/C Mode - Front Auxiliary HVAC Control Assembly Only

The auxiliary temperature switch in the front auxiliary HVAC control assembly allows the vehicle operator to adjust the temperature in the rear of the vehicle. Power is provided to both the front auxiliary HVAC control assembly and the auxiliary air temperature actuator from the IP fuse block on the ignition 3 voltage circuit.

Voltage delivered to the front auxiliary HVAC control assembly on the ignition 3 voltage circuit is sent to a variable resistor. Based on the placement of the temperature switch, a varied voltage is sent to the auxiliary air temperature actuator on the auxiliary air temperature door control circuit. The auxiliary air temperature actuator positions the temperature door to divert the appropriate amount of air past the heater core in order to achieve the desired temperature.

A/C Mode - Front Auxiliary HVAC Control Assembly with Rear Auxiliary HVAC Control Assembly

The auxiliary temperature switch in the front auxiliary HVAC control assembly allows the vehicle operator to adjust the temperature in the rear of the vehicle. Power is provided to both the front auxiliary HVAC control assembly and the auxiliary air temperature actuator from the IP fuse block on the ignition 3 voltage circuit.

Voltage delivered to the front auxiliary HVAC control assembly on the ignition 3 voltage circuit is sent to a variable resistor. Based on the placement of the temperature switch, a varied voltage is sent to the auxiliary air temperature actuator on the auxiliary air temperature door control circuit, and auxiliary HVAC control processor. The auxiliary air temperature actuator positions the temperature door to divert the appropriate amount of air past the heater core in order to achieve the desired temperature.

A/C Mode - Read Auxiliary HVAC Control Assembly

The auxiliary temperature switch in the rear auxiliary HVAC control assembly allows the rear seat passengers to adjust the temperature in the rear of the vehicle. Power is provided to the rear auxiliary HVAC control assembly, auxiliary HVAC control processor and the auxiliary air temperature actuator from the IP fuse block on the ignition 3 voltage circuit.

To activate the rear auxiliary HVAC control assembly, the front auxiliary HVAC control assembly must be placed in the REAR CNTL position. Ignition 3 voltage is sent to the auxiliary HVAC control processor. When the switch is placed in the REAR CNTL position, the voltage is grounded through the auxiliary blower motor switch control, front auxiliary HVAC control assembly and the ground circuit to allow the rear auxiliary HVAC control assembly to operate the auxiliary temperature actuator. Voltage delivered to the rear auxiliary HVAC control assembly on the ignition 3 voltage circuit is sent to a varied resistor. Based on the placement of the temperature switch, a varied voltage is sent to the auxiliary air temperature actuator on the auxiliary air temperature door control circuit, and auxiliary HVAC control processor. The auxiliary air temperature actuator positions the temperature door to divert the appropriate amount of air past the heater core in order to achieve the desired temperature.

Engine Coolant

Engine coolant is the key element of the heating system. The thermostat controls engine operating coolant temperature. The thermostat also creates a restriction for the cooling system that promotes a positive coolant flow and helps prevent cavitation. Coolant enters the heater core through the inlet heater hose, in a pressurized state.

The heater core is located inside the HVAC module. The heat of the coolant flowing through the heater core is absorbed by the ambient air drawn through the HVAC module. Heated air is distributed to the passenger compartment, through the HVAC module, for passenger comfort.

The amount of heat delivered to the passenger compartment is controlled by opening or closing the HVAC module air temperature door. The coolant exits the heater core through the return heater hose and recirculated back through the engine cooling system.

A/C Cycle

Refrigerant is the key element in an air conditioning system. R-134a is presently the only EPA approved refrigerant for automotive use. R-134a is an very low temperature gas that can transfer the undesirable heat and moisture from the passenger compartment to the outside air.

The A/C compressor is belt driven and operates when the magnetic clutch is engaged. The compressor builds pressure on the vapor refrigerant. Compressing the refrigerant also adds heat to the refrigerant. The refrigerant is discharged from the compressor, through the discharge hose, and forced to flow to the condenser and then through the balance of the A/C system. The A/C system is mechanically protected with the use of a high pressure relief valve. If the high pressure switch were to fail or if the refrigerant system becomes restricted and refrigerant pressure continued to rise, the high pressure relief will pop open and release refrigerant from the system.

Compressed refrigerant enters the condenser in a high temperature, high pressure vapor state. As the refrigerant flows through the condenser, the heat of the refrigerant is transferred to the ambient air passing through the condenser. Cooling the refrigerant causes the refrigerant to condense and change from a vapor to a liquid state.

The condenser is located in front of the radiator for maximum heat transfer. The condenser is made of aluminum tubing and aluminum cooling fins, which allows rapid heat transfer for the refrigerant. The semi-cooled liquid refrigerant exits the condenser and flows through the liquid line, to the orifice tube.

The orifice tube is located in the liquid line between the condenser and the evaporator. The orifice tube is the dividing point for the high and the low pressure sides of the A/C system. As the refrigerant passes through the orifice tube, the pressure on the refrigerant is lowered. Due to the pressure differential on the liquid refrigerant, the refrigerant will begin to vaporize at the orifice tube. The orifice tube also meters the amount of liquid refrigerant that can flow into the evaporator.

Refrigerant exiting the orifice tube flows into the evaporator core in a low pressure, liquid state. Ambient air is drawn through the HVAC module and passes through the evaporator core. Warm and moist air will cause the liquid refrigerant boil inside of the evaporator core. The boiling refrigerant absorbs the moisture and heat from the ambient air. The refrigerant exits the evaporator through the suction line and back to the compressor, in a vapor state, and completing the A/C cycle of heat removal. At the compressor, the refrigerant is compressed again and the cycle of heat removal is repeated.

The conditioned air is distributed through the HVAC module for passenger comfort. The heat and moisture removed from the passenger compartment will also change form, or condense, and is discharged from the HVAC module as water.

A/C Cycle with Auxiliary

The auxiliary A/C system operates from the vehicles primary A/C system. The front or primary A/C system must be ON to allow the rear A/C system to function.

Refrigerant is the key element in an air conditioning system. R-134a is presently the only EPA approved refrigerant for automotive use. R-134a is an very low temperature gas that can transfer the undesirable heat and moisture from the passenger compartment to the outside air.

The A/C system used on this vehicle is a non cycling system. Non cycling A/C systems use a high pressure switch to protect the A/C system from excessive pressure. The high pressure switch will OPEN the electrical signal, to the compressor clutch, in the event that the refrigerant pressure becomes excessive. After the high and low side of the A/C system pressure equalize, the high pressure switch will CLOSE. Closing the high pressure switch will complete the electrical circuit to the compressor clutch. The A/C system is also mechanically protected with the use of a high pressure relief valve. If the high pressure switch were to fail or if the refrigerant system becomes restricted and refrigerant pressure continued to rise, the high pressure relief will pop open and release refrigerant from the system.

The A/C compressor is belt driven and operates when the magnetic clutch is engaged. The compressor builds pressure on the vapor refrigerant. Compressing the refrigerant also adds heat to the refrigerant. The refrigerant is discharged from the compressor, through the discharge hose, and forced to flow to the condenser and then through the balance of the A/C system.

Compressed refrigerant enters the condenser in a high temperature, high pressure vapor state. As the refrigerant flows through the condenser, the heat of the refrigerant is transferred to the ambient air passing through the condenser. Cooling the refrigerant causes the refrigerant to condense and change from a vapor to a liquid state.

The condenser is located in front of the radiator for maximum heat transfer. The condenser is made of aluminum tubing and aluminum cooling fins, which allows rapid heat transfer for the refrigerant. The semi-cooled liquid refrigerant exits the condenser and flows through the liquid line. The liquid line flow is split and the liquid refrigerant flows to both the front or primary A/C system, and to the liquid line for the rear A/C system.

The liquid refrigerant, flowing to the rear A/C system, flows into the rear TXV. The rear TXV is located at the rear evaporator inlet. The TXV is the dividing point for the high and the low pressure sides of the rear A/C system. As the refrigerant passes through the TXV, the pressure on the refrigerant is lowered. Due to the pressure differential on the liquid refrigerant, the refrigerant will begin to boil at the expansion device. The TXV also meters the amount of liquid refrigerant that can flow into the evaporator.

Refrigerant exiting the TXV flows into the evaporator core in a low pressure, liquid state. Ambient air is drawn through the rear A/C module and passes through the evaporator core. Warm and moist air will cause the liquid refrigerant boil inside of the evaporator core. The boiling refrigerant absorbs the moisture and heat from the ambient air. The refrigerant exits the evaporator through the suction line and back to the primary A/C system suction line. Refrigerant in the primary A/C system suction line flows back to the compressor, in a vapor state, and completes the A/C cycle of heat removal. At the compressor, the refrigerant is compressed again and the cycle of heat removal is repeated.

The conditioned air is distributed through the rear A/C module for passenger comfort. The heat and moisture removed from the rear passenger compartment will also change form, or condense, and is discharged from the rear A/C module as water.

Scheme 303

See also:
• TESTING FOR INTERMITTENT AND POOR CONNECTIONS
• LEAK TESTING
• DEFROSTING INSUFFICIENT
• REFRIGERANT RECOVERY AND RECHARGING
• Air Delivery Description and Operation
• Air Temperature Description and Operation
• HVAC Compressor Clutch Does Not Engage
• HVAC Compressor Clutch Does Not Disengage
• Blower Motor Always On
• Blower Motor Inoperative
• Blower Motor Always On - Auxiliary (Passenger Van w/Aux)
• Blower Motor Malfunction - Auxiliary
• Too Hot in Vehicle
• Too Cold in Vehicle
• Too Hot in Vehicle - Auxiliary (Passenger Van w/Aux)
• Too Cold in Vehicle - Auxiliary (Passenger Van w/Aux)