Heating, Ventilation and Air Conditioning Chevrolet Chevy Express G3500

Fastener Tightening Specifications

Fastener Tightening Specifications

Refrigerant System Capacities

Refrigerant System Capacities

The Heating, Ventilation and Air Conditioning (HVAC) system is divided into two separate sections. The first, Heating, Ventilation and Air Conditioning, has all procedures that pertain to a HVAC component or function that is not specifically associated with the manual control system. The second, HVAC Systems - Manual, has all procedures specific to the manual control system.

Begin the system diagnosis with the Symptoms - HVAC Systems - Manual in HVAC Systems - Manual.

Review the Description and Operation information to help you determine the correct symptom diagnostic procedure when a malfunction exists. Reviewing the Description and Operation information will also help you determine if the condition described by the customer is normal operation. The HVAC Description and Operation information is divided into

1. «Air Delivery Description and Operation»(/chevrolet/chevy-express-g3500/1996-2012/remont/manual-hvac-system/#hvac-systems-manual__air-delivery-description-and-operation) in HVAC Systems - Manual
2. «Air Temperature Description and Operation»(/chevrolet/chevy-express-g3500/1996-2012/remont/manual-hvac-system/#hvac-systems-manual__air-temperature-description-and-operation) in HVAC Systems - Manual

The Air Delivery Description and Operation contains the following topics

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

The Air temperature Description and Operation contains the following topics

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

Leak Testing

Tools Required

1. J 39400-A Halogen Leak Detector. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. J 41447 Leak Detection Dye. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
3. J 42220 Leak Detection Lamp. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
4. J 43872 Fluorescent Dye Cleaner. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
5. J 46297 A/C Dye Injector Kit. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
6. J 46297-12 Replacement Dye Cartridges. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

Refrigerant Leak Testing

The fluorescent dye mixes and flows with the polyalkylene glycol (PAG) oil throughout the refrigerant system.

Verifying some passive leaks may require using the J 39400-A , even though the A/C system contains fluorescent dye. See Special Tools and Equipment .

The only time that adding additional fluorescent dye is required is after flushing the A/C system.

Fluorescent Leak Detector

Fluorescent dye will assist in locating any leaks in the A/C system.

1. Condensation on the evaporator core or the refrigerant lines may wash the PAG oil and fluorescent dye away from the actual leak. Condensation may also carry dye through the HVAC module drain.
2. Leaks in the A/C system will be indicated in a light green or yellow color when using the leak detection lamp. Use the leak detection lamp in the following areas: All fittings or connections that use seal washers or O-rings All of the A/C components The A/C compressor shaft seal The A/C hoses and pressure switches The HVAC module drain tube, if the evaporator core is suspected of leaking The service port sealing caps The sealing cap is the primary seal for the service ports.
3. Follow the instructions supplied with the J 42220 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
4. To prevent false diagnosis in the future, thoroughly clean the residual dye from any area where leaks were found. Use a rag and the approved J 43872 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

Fluorescent Dye Injection

1. Not all of the fluorescent dyes are compatible with PAG oil. Some types of dye decrease the oil viscosity or may chemically react with the oil.
2. R-134A leak detection dye requires time to work. Depending upon the leak rate, a leak may not become visible for between 15 minutes and 7 days.
3. To prevent false diagnosis, thoroughly clean any residual dye from the service port with a rag and the approved fluorescent dye cleaner J 43872 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

Halogen Leak Detector

Ensure that the vehicle has at least 0.45 kg (1 lb) of refrigerant in the A/C refrigeration system in order to perform a leak test. Refer to Refrigerant Recovery and Recharging for recharging the A/C system.

Clean and dry all surfaces in order to prevent a false warning. Liquids will damage the detector.

Follow the instructions supplied with the J 39400-A . See Special Tools and Equipment .

Air Conditioning (A/C) System Performance Test

This test measures the operating efficiency of the A/C system under the following conditions

1. The current ambient air temperature
2. The current relative humidity
3. The high side pressure of the A/C system
4. The low side pressure of the A/C system
5. The temperature of the air being discharged into the passenger compartment

Test Description

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

1. 1: This step determines if the A/C system has at least the minimum refrigerant charge required to operate the system without damage.
2. 2: This step measures the performance of the A/C system.
3. 3: This step is to allow for vehicle variations as well as high ambient temperatures.

Air Conditioning (A/C) System Performance Test

A/C Performance Table - Front Only

Scheme 3

A/C Performance Table - With Rear A/C

Scheme 4

Air Conditioning (A/C) Diagnostics - Pressure Zone A

Air Conditioning (A/C) Diagnostics - Pressure Zone A

Air Conditioning (A/C) Diagnostics - Pressure Zone B

Air Conditioning (A/C) Diagnostics - Pressure Zone B

Air Conditioning (A/C) Diagnostics - Pressure Zone C

Air Conditioning (A/C) Diagnostics - Pressure Zone C

Air Conditioning (A/C) Diagnostics - Pressure Zone D

Air Conditioning (A/C) Diagnostics - Pressure Zone D

Heating Performance Diagnostic

Heating Performance Diagnostic

Defrosting Insufficient

Defrosting Insufficient

Noise Diagnosis - Blower Motor

Noise Diagnosis - Blower Motor

Noise Diagnosis - Air Conditioning (A/C) System

Noise Diagnosis - Air Conditioning (A/C) System

Noise Diagnosis - HVAC Module

Noise Diagnosis - HVAC Module

Odor Diagnosis

Odor Diagnosis

Eliminating Air Conditioning Odor

Odors may be emitted from the air conditioning system primarily at start up in hot, humid climates. The following conditions may cause the odor

1. Debris is present in the A/C Evaporator and Blower Module
2. Microbial growth on the evaporator core

When the blower motor fan is turned on, the microbial growth may release an unpleasant musty odor into the passenger compartment. To remove odors of this type, the mirocbial growth must be eliminated. Perform the following procedure

Deodorize the evaporator core using Deodorizing Aerosol Kit.

Perform the following steps in order to deodorize the A/C system

1. Ensure that the plenum that draws outside air into the A/C Evaporator and Blower Module is clear of debris.
2. Disable the A/C compressor clutch operation by disconnecting the clutch coil electrical connector.
3. Dry the evaporator core by performing the following steps: Start the engine. Select the maximum temperature setting. Select the recirculation mode. Run the blower motor on high for 10 minutes.
4. Locate an area in the air conditioning duct between the blower motor and the evaporator core downstream of the blower motor.
5. Drill a 3.175 mm (0.125 in) hole where the hole will not interfere with or damage the following components: The blower motor The evaporator core Any other operating part the of system
6. Wear safety goggles and latex gloves in order to perform the following actions: Select the maximum blower speed. Insert the deodorizer extension tube into the hole to the mark on the extension tube. Use short spray bursts and vary the direction of spray for a 2-3 minute period of time.
7. Shut the engine OFF. Allow the vehicle to sit for 3-5 minutes.
8. Seal the 3.175 mm (0.125 in) hole with body sealer or RTV gasket compound.
9. Start the engine.
10. Operate the blower motor on high for 15-20 minutes to dry.
11. Reconnect the A/C compressor clutch coil electrical connector.
12. Verify proper clutch operation.

Refrigerant Recovery and Recharging

Tools Required

1. J 43600 ACR 2000 Air Conditioning Service Center. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. J 45037 A/C Oil Injector. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

Note. R-134a is the only approved refrigerant for use in this vehicle. The use of any other refrigerant may result in poor system performance or component failure.

Note. To avoid system damage use only R-134a dedicated tools when servicing the A/C system.

Note. Use only Polyalkylene Glycol Synthetic Refrigerant Oil (PAG) for internal circulation through the R-134a A/C system and only 525 viscosity mineral oil on fitting threads and O-rings. If lubricants other than those specified are used, compressor failure and/or fitting seizure may result.

Note. R-12 refrigerant and R-134a refrigerant must never be mixed, even in the smallest of amounts, as they are incompatible with each other. If the refrigerants are mixed, compressor failure is likely to occur. Refer to the manufacturer instructions included with the service equipment before servicing.

The J 43600 is a complete air conditioning service center for R-134a. The ACR 2000 recovers, recycles, evacuates and recharges A/C refrigerant quickly, accurately and automatically. The unit has a display screen that contains the function controls and displays prompts that will lead the technician through the recover, recycle, evacuate and recharge operations. R-134a is recovered into and charged out of an internal storage vessel. The ACR 2000 automatically replenishes this vessel from an external source tank in order to maintain a constant 5.45-6.82 kg (12-15 lbs) of A/C refrigerant. See Special Tools and Equipment .

The ACR 2000 has a built in A/C refrigerant identifier that will test for contamination, prior to recovery and will notify the technician if there are foreign gases present in the A/C system. If foreign gases are present, the ACR 2000 will not recover the refrigerant from the A/C system.

The ACR 2000 also features automatic air purge, single pass recycling and an automatic oil drain.

Refer to the J 43600 ACR 2000 manual for operation and setup instruction. Always recharge the A/C System with the proper amount of R-134a. See Special Tools and Equipment . Refer to Refrigerant System Capacities for the correct amount.

A/C Refrigerant System Oil Charge Replenishing

If oil was removed from the A/C system during the recovery process or due to component replacement, the oil must be replenished. Oil can be injected into a charged system using J 45037 . See Special Tools and Equipment . For the proper quantities of oil to add to the A/C refrigerant system, refer to Refrigerant System Capacities .

Flushing

Tools Required

1. J 43600 Air Conditioning Service Center. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. J 45268 Flush Adapter Kit. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
3. J 41447 Leak Detection Dye. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
4. J 42220 Universal 12V Leak Detection Lamp. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

Flushing is intended to remove the following

1. Contaminated polyalkylene glycol (PAG) oil
2. Desiccant, following a desiccant bag failure
3. Overcharge of PAG oil
4. Refrigerant contamination

1. Recover the refrigerant. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Remove the orifice tube. Refer to «Expansion (Orifice) Tube Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__expansion-orifice-tube-replacement) .
3. Connect the A/C lines with the orifice tube removed.
4. Remove the A/C compressor. Refer to «Compressor Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Compressor Replacement (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
5. Inspect the end of the suction hose for a suction screen.
6. Remove the suction screen, if installed.
7. Install the J 45268-3 to the A/C compressor hose assembly.
8. Forward flow refrigerant flushing is recommended for contaminated refrigerant or PAG oil. Perform the following procedure: IMPORTANT: The filter inside the J 45268-1 is serviceable. Remove and discard the check valve from the filter. Service the filter with ACDelco P/N GF 470, before each flush. Connect the J 45268-1 lush filter to the suction port of the J 45268-3 flush adapter. Connect the blue hose from the J 43600 to the J 45268-1 flush filter adapter. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) . Connect the red hose from the J 43600 to the J 45268-3 flush adapter. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
9. Reverse flow refrigerant flushing is recommended for desiccant bag failure. Perform the following procedure and replace the accumulator when the flush procedure is complete. IMPORTANT: The filter inside the J 45268-1 is serviceable. Remove and discard the check valve from the filter. Service the filter with ACDelco P/N GF 470, before each flush. Connect the J 45268-1 flush filter to the discharge port of the J 45268-3 flush adapter. Connect the blue hose from the J 43600 to the J 45268-1 flush filter adapter. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) . Connect the red hose from the J 43600 to the suction port of the J 45268-3 flush adapter. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
10. Flush the front A/C system. Follow the instructions supplied with the J 43600 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) . Close the valve on the external refrigerant tank, before starting the flush process.
11. If the vehicle is equipped with rear A/C, flush the auxiliary A/C system separately.
12. Cut the orifice tube frame and screen, enough to access the end of the orifice tube. Pinch off the orifice tube.
13. Install the pinched orifice tube. Refer to «Expansion (Orifice) Tube Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__expansion-orifice-tube-replacement) .
14. Remove the auxiliary thermostatic expansion valve (TXV). Refer to «Thermal Expansion Valve Replacement - Auxiliary»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
15. Install the J 45268-104.
16. Install the auxiliary evaporator core to the A/C lines.
17. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
18. Connect the auxiliary A/C lines to the auxiliary evaporator core.
19. Lower the vehicle.
20. Flush the auxiliary A/C system. Follow the instructions supplied with the J 43600 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
21. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
22. Remove the auxiliary A/C lines from the auxiliary evaporator core.
23. Lower the vehicle.
24. Remove the J 45268-104.
25. Inspect the TXV for debris. Clean or replace, as needed.
26. Install the auxiliary TXV. Refer to «Thermal Expansion Valve Replacement - Auxiliary»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
27. Remove the J 45268-3 from the A/C compressor hose assembly.
28. 13. Drain the PAG oil from the A/C compressor. Rotate the compressor input shaft to assist in draining the PAG oil from the compressor.
29. 14. Add back the total system capacity of PAG oil to the A/C compressor. Refer to «Refrigerant System Capacities»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-system-capacities) .
30. If you will be replacing the A/C compressor after flushing the system, perform the following procedure: Determine if the new service compressor is shipped with PAG oil. Refer to «Refrigerant System Capacities»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-system-capacities) . If the service compressor is shipped with PAG oil, DO NOT drain the new PAG oil from the compressor. Deduct the amount of PAG oil shipped with the service compressor from the amount of PAG oil listed in the capacities table. Refer to «Refrigerant System Capacities»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-system-capacities) . Add the calculated amount to the compressor, as needed.
31. Add one bottle of J 41447 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
32. Install the A/C compressor. Refer to «Compressor Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Compressor Replacement (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
33. Install a new orifice tube. Refer to «Expansion (Orifice) Tube Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__expansion-orifice-tube-replacement) .
34. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
35. Leak test the fittings using the J 42220 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

Draining Procedure

1. Drain the oil from both the suction and discharge ports of the removed compressor into a clean, graduated container. Rotate the compressor shaft to assist in draining the compressor.
2. Measure and record the amount of oil drained from the removed compressor. This measurement will be used during installation of the replacement compressor.
3. Properly discard the used refrigerant oil.

Balancing Procedure

1. The replacement compressor is shipped with the total system capacity of refrigerant oil.
2. Before installing the compressor, the refrigerant oil will have to be partially drained: Refer to the amount of refrigerant oil recorded during the compressor removal. Subtract the amount recorded from the total system capacity. Refer to «Refrigerant System Capacities»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-system-capacities) . The difference between the total system capacity and the recorded amount is the calculated amount to be drained from the replacement compressor.
3. Drain the calculated amount of refrigerant oil from the replacement compressor.

Tools Required

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

Removal Procedure

1. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
2. Recover the refrigerant from the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
3. Disconnect the clutch coil electrical connector (1) from the compressor.
4. Disconnect the A/C high pressure switch electrical connector (2) from the compressor.
5. Remove the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) in Engine Mechanical - 4.3L.
6. Remove the compressor hose assembly.
7. Remove the mounting bolts (2) from the compressor.
8. Remove the compressor from the vehicle.
9. If replacing the compressor, balance the refrigerant oil. Refer to «Compressor Oil Balancing»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

Installation Procedure

1. Install the compressor (1) to the vehicle.
2. Install the compressor retaining bolts to the mounting bracket. Tighten: Tighten the bolts to 50 N.m (37 lb ft).
3. Install the new sealing washers. Refer to «Sealing Washer Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
4. Install the compressor hose assembly.
5. Install the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) in Engine Mechanical - 4.3L.
6. Connect the clutch coil electrical connector (1) to the compressor.
7. Connect the A/C high pressure switch electrical connector (2) to the compressor.
8. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
9. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
10. Leak test the fittings of the components using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Recover the refrigerant from the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Remove the splash shield.
4. Install a ratchet into the air conditioning (A/C) belt tensioner adapter opening.
5. Rotate the belt tensioner clockwise in order to relieve the tension on the belt.
6. Remove the A/C belt from the pulley.
7. Remove the lower compressor mounting bolts.
8. Partially lower the vehicle to access the compressor through the wheel opening.
9. Remove the suction hose bolt.
10. Remove the suction hose from the compressor.
11. Remove the discharge hose bolt from the compressor.
12. Remove the discharge hose from the compressor.
13. Remove the upper compressor mounting bolts.
14. Disconnect the compressor clutch electrical connector.
15. Disconnect the high pressure switch connector.
16. Lower the vehicle.
17. Remove the fan shroud. Refer to «Fan Shroud Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
18. Remove the compressor.
19. Remove the compressor sealing washers. Discard the compressor sealing washers.
20. If replacing the compressor, balance the refrigerant oil. Refer to «Compressor Oil Balancing»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

1. Install the compressor with the mounting bolts in the compressor. Tighten: Tighten the bolts to 50 N.m (37 lb ft).
2. Install the fan shroud. Refer to «Fan Shroud Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
3. Install the new sealing washers. Refer to «Sealing Washer Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
4. Install the suction hose to the compressor.
5. Install the suction line bolt to the compressor. Tighten: Tighten the bolt to 35 N.m (26 lb ft).
6. Install the discharge hose to the compressor.
7. Install the discharge line bolt to the compressor. Tighten: Tighten the bolt to 35 N.m (26 lb ft).
8. Connect the compressor clutch electrical connector.
9. Connect the high pressure switch connector.
10. Install a ratchet into the air conditioning (A/C) belt tensioner adapter opening.
11. Rotate the belt tensioner clockwise in order to install the belt.
12. Install the A/C belt on to the pulley.
13. Install the splash shield.
14. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
15. Leak test the fittings of the component using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

1. Remove the clutch plate retaining bolt (1).
2. Remove the clutch plate assembly.
3. Remove the clutch hub/bearing snap ring.
4. Remove the clutch hub/bearing assembly.
5. Remove the clutch coil connector bracket retaining screw.
6. Remove the clutch coil snap ring.
7. Remove the clutch coil assembly.

1. Install the coil assembly to the compressor.
2. Install the coil snap ring.
3. Install the coil connector retaining bracket screw. Tighten: Tighten the screw to 9 N.m (80 lb in).
4. Install the clutch hub/bearing assembly.
5. Install the clutch hub/bearing snap ring.
6. Install the clutch plate assembly.
7. Install the clutch plate retaining bolt (1). Tighten: Tighten the bolt to 18 N.m (13 lb ft).

1. Remove the compressor. Refer to «Compressor Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Compressor Replacement (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Remove the compressor mounting bracket bolts (3).
3. Remove the compressor mounting bracket (2).

1. Install the compressor mounting bracket (2).
2. Install the compressor mounting bracket bolts (3). Tighten: Tighten the bolts to 50 N.m (37 lb ft).
3. Install the compressor. Refer to «Compressor Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Compressor Replacement (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

1. Remove the seal washer from the A/C refrigerant component.
2. Inspect the seal washer for signs of damage to help determine the root cause of the failure.
3. Inspect the A/C refrigerant components for damage or burrs. Repair if necessary.
4. Discard the sealing washer.

1. Inspect the new seal washer for any signs of cracks, cuts, or damage. Do not use a damaged seal washer.
2. Remove the cap or tape from the A/C refrigerant components.
3. Using a lint-free clean, dry cloth, clean the sealing surfaces of the A/C refrigerant components.
4. Carefully install the new seal washer onto the A/C refrigerant component. The washer must completely bottom against the surface of the fitting.
5. Assemble the remaining A/C refrigerant components. Refer to the appropriate repair procedure.

1. Disassemble the A/C refrigerant components. Refer to the appropriate repair procedure For compression style fittings use a back up wrench on the fitting (2) and loosen the fitting nut (1). For banjo style fittings remove the bolt retaining the banjo type fitting.
2. Remove the O-ring seal from the A/C refrigerant component.
3. Inspect the O-ring seal for signs of damage to help determine the root cause of the failure.
4. Inspect the A/C refrigerant components for damage or burrs. Repair if necessary.
5. Cap or tape the A/C refrigerant components.
6. Discard the O-ring seal.

1. Inspect the new O-ring seal for any sign or cracks, cuts, or damage. Replace if necessary.
2. Remove the cap or tape from the A/C refrigerant components.
3. Using a lint-free clean, dry cloth, carefully clean the sealing surfaces of the A/C refrigerant components.
4. Lightly coat the new O-ring seal with mineral base 525 viscosity refrigerant oil.
5. Carefully slide the new O-ring seal onto the A/C refrigerant component.
6. The O-ring seal must be fully seated.
7. Assemble the A/C components. Refer to the appropriate repair procedure. For compression style fittings use a back up wrench on the fitting (2) and tighten the fitting nut (1) to specification. For banjo style fittings install the bolt retaining the banjo type fitting and tighten to specification.

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Recover the refrigerant. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
3. Remove the grille. Refer to «Grille Replacement (Uplevel)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) or «Grille Replacement (Base)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) in Exterior Trim.
4. Remove the discharge line nut (2) from the condenser.
5. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
6. Remove the discharge line bolt from the compressor.
7. Lower the vehicle.
8. Remove the discharge line from the vehicle.

1. Install the discharge hose into the vehicle.
2. Install the discharge hose nut (2) to the condenser. Tighten: Tighten the nut to 16 N.m (12 lb ft).
3. Install the grille. Refer to «Grille Replacement (Uplevel)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) or «Grille Replacement (Base)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) in Exterior Trim.
4. Raise the vehicle.
5. Install the discharge hose to the compressor.
6. Install the discharge hose to the compressor bolt. Tighten: Tighten the bolt to 35 N.m (26 lb ft).
7. Lower the vehicle.
8. Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
9. Leak test the fittings of the component using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Recover the refrigerant. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
3. Remove the headlight capsule. Refer to «Headlamp Capsule Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exterior-lights/#lighting-systems) in Lighting Systems.
4. Remove the discharge line nut (2) from the condenser.
5. Remove the discharge line bolt from the compressor.
6. Remove the discharge line from the vehicle.

1. Install the discharge hose into the vehicle.
2. Install the discharge hose nut (2) to the condenser. Tighten: Tighten the nut to 16 N.m (12 lb ft).
3. Install the headlight capsule. Refer to «Headlamp Capsule Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exterior-lights/#lighting-systems) in Lighting Systems.
4. Install the discharge hose to the compressor.
5. Install the discharge hose to the compressor bolt. Tighten: Tighten the bolt to 35 N.m (26 lb ft).
6. Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
7. Leak test the fittings of the component using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Recover the refrigerant. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
3. Remove the suction line nut (1) from the accumulator.
4. Remove the rear suction line nut (2) if equipped with rear air.
5. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
6. Remove the suction line bolt from the compressor.
7. Remove the suction line from the vehicle.

1. Install the suction line into the vehicle.
2. Install the suction line bolt to the compressor. Tighten: Tighten the bolt to 35 N.m (26 lb ft).
3. Lower the vehicle.
4. Install the rear suction line nut (2) if equipped with rear air. Tighten: Tighten the bolt to 16 N.m (12 lb ft).
5. Install the suction line nut (1) to the accumulator. Tighten: Tighten the nut to 16 N.m (12 lb ft).
6. Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
7. Leak test the fittings of the component using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Recover the refrigerant from the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Remove the coolant recover reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
3. Remove the grille. Refer to «Grille Replacement (Uplevel)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) or «Grille Replacement (Base)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) in Exterior Trim.
4. Remove the front evaporator hose nut (1) from the condenser.
5. Remove the evaporator inlet hose nut (1) from the front evaporator tube hose.
6. Remove the evaporator inlet hose from the front hose.
7. Remove the nut from the rear evaporator tube.
8. Remove the front evaporator hose from the vehicle.
9. Remove the sealing washers.

1. Install the new sealing washers. Refer to «Sealing Washer Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Install the front evaporator tube into the vehicle.
3. Install the front evaporator tube to the rear evaporator tube.
4. Install the rear evaporator tube retaining nut (1). Tighten: Tighten the nut to 16 N.m (12 lb ft).
5. Install the evaporator inlet hose to the front evaporator tube.
6. Install the evaporator inlet hose nut to the front evaporator tube. Tighten: Tighten the nut (1) to 16 N.m (12 lb ft).
7. Install the front evaporator tube to the condenser.
8. Install the front evaporator tube nut (1) to the condenser. Tighten: Tighten the nut to 16 N.m (12 lb ft).
9. Install the grille. Refer to «Grille Replacement (Uplevel)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) or «Grille Replacement (Base)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) in Exterior Trim.
10. Install the coolant recover reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
11. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
12. Leak test the fittings of the components using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Recover the refrigerant from the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Remove the coolant recover reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
3. Remove the evaporator inlet hose nut (1) from the evaporator.
4. Remove the evaporator inlet hose clip screw (2).
5. Remove the evaporator inlet hose retaining nut from the front hose.
6. Remove the evaporator inlet hose from the vehicle.
7. Remove the sealing washers.

1. Install the new sealing washers. Refer to «Sealing Washer Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Install the evaporator inlet hose in to the vehicle.
3. Install the evaporator inlet hose to the evaporator.
4. Install the evaporator inlet hose retaining nut (1). Tighten: Tighten the nut to 16 N.m (12 lb ft).
5. Install the evaporator inlet hose fitting to the front evaporator tube. Tighten: Tighten the fitting to 16 N.m (12 lb ft).
6. Install the screw into evaporator hose clip (1). Tighten: Tighten the fitting to 6 N.m (53 lb in).
7. Install the coolant recover reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
8. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
9. Leak test the fittings of the components using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Recover the refrigerant from the system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
3. Remove the auxiliary evaporator outlet tube (1) from the compressor hose (3).
4. Remove the retaining nut form the engine.
5. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
6. Remove the auxiliary evaporator tube (1) retaining nuts (2) from the body.
7. Remove the bolt retaining the auxiliary evaporator outlet tube to the transmission bracket.
8. Remove the auxiliary evaporator outlet tube from the auxiliary evaporator.
9. Remove the evaporator tube from the vehicle.

1. Connect the evaporator tube (1) to the auxiliary evaporator core. Tighten: Tighten the hose fitting to 48 N.m (35 lb ft).
2. Install the evaporator tube retaining nuts (2) to the engine and the body. Tighten: Tighten the retaining nuts to 6 N.m (53 lb in).
3. Install the bolt retaining the hose (1) to the transmission bracket. Tighten: Tighten the retaining bolt to 5 N.m (44 lb in).
4. Lower the vehicle.
5. Install the auxiliary evaporator outlet tube to the compressor hose. Tighten: Tighten the fitting to 48 N.m (35 lb ft).
6. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
7. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
8. Leak test the fittings of the components using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Recover the refrigerant from the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Remove the condenser tube from the condenser.
3. Measure 20 mm (0.75 in) from the bend on the condenser tube (3). Mark the tube.
4. Measure 42 mm (1.65 in) from the mark on the condenser tube (3) from the previous step. Mark the tube.
5. Using a tubing cutter, cut the marked section of the condenser tube (3).
6. Remove the burrs from the condenser tube (3).
7. Remove the nuts (4), the ferrules, and the O-rings (2) from the A/C refrigerant filter (1).
8. Push the proper size nuts (4) and ferrules (3) over each of the condenser tube halves.
9. Install the ferrules (3) with the small end toward the nut (4).
10. Install the A/C refrigerant filter (1) to the condenser tube with the flow arrow pointing toward the evaporator.
11. While holding the condenser tube in the A/C refrigerant filter (1), tighten the nuts (4) to the A/C refrigerant filter. Tighten: Tighten the nuts to 34 N.m (25 lb ft).
12. Remove the nuts (4) from the A/C refrigerant filter (1).
13. Install the O-rings (2) to the condenser tube. Refer to «O-Ring Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
14. Install the nuts (4) to the A/C refrigerant filter (1). Tighten: Tighten the nuts to 34 N.m (25 lb ft).
15. Install the condenser tube to the condenser.
16. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
17. Leak test the fittings of the component using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Recover the refrigerant from the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Remove the front evaporator tube. Refer to «Evaporator Tube Replacement - Front»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
3. Remove the nuts (4) from the A/C refrigerant filter (1).
4. Remove the A/C refrigerant filter from the condenser tube.

1. Install the O-rings. Refer to «O-Ring Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Install the A/C refrigerant filter to the condenser tube with the flow arrow pointing towards the evaporator.
3. Install the nuts (4) to the A/C refrigerant filter (1). Tighten: Tighten the nuts to 34 N.m (25 lb ft).
4. Install the front evaporator tube. Refer to «Evaporator Tube Replacement - Front»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
5. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
6. Leak test the fittings of the installed component using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

Expansion (Orifice) Tube Replacement

Tools Required

1. J 26549-E Orifice Tube Remover and Installer. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. J 39400-A Halogen Leak Detector. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

1. Recover the refrigerant from the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Remove the evaporator hose retaining nut from the evaporator.
3. Use the J 26549-E in order to remove the expansion tube (1). See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
4. If the expansion tube is stuck perform the following: Remove as much of the impacted residue as possible. Carefully apply heat with a heat gun, or hair dryer 7 mm (0.25 in) from the dimples on the inlet pipe. DO NOT overheat the pipe. While applying heat, use the J 26549-E in order to grip the expansion tube. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) . Use a turning motion along with a push-pull motion to loosen the impacted expansion tube and remove.

1. Use the J 26549-E in order to install the expansion tube. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Install new sealing washers to the evaporator tube. Refer to «Sealing Washer Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
3. Install the evaporator hose to the evaporator.
4. Install the evaporator hose retaining nut to the evaporator. Tighten: Tighten the nut to 16 N.m (12 lb ft).
5. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
6. Leak test the fittings of the components using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

1. Remove the cover from the relay center.
2. Remove the compressor relay (2).

1. Install the compressor relay (2).
2. Install the cover on the relay center.

Air Conditioning (A/C) High Pressure Switch Replacement

Tools Required

1. J 5403 Snap Ring Pliers. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. J 9553-01 O-Ring Remover. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
3. J 39400-A Halogen Leak Detector. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

1. Recover the refrigerant from the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Clean the control A/C high pressure switch area before removing the snap ring.
3. Disconnect the electrical connector from the A/C high pressure switch (2).
4. Remove the A/C high pressure switch snap ring using the J 5403 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
5. Remove the A/C high pressure switch (2) from the compressor.
6. Remove the old O-ring seal from the A/C high pressure switch cavity using the J 9553-01 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
7. Inspect the A/C high pressure switch cavity and the O-ring groove in the rear head for dirt or foreign material. Clean the components as necessary.

1. Lubricate the new O-ring using new 525 viscosity refrigerant oil.
2. Install the new O-ring into the groove in the switch cavity.
3. Lubricate the control switch housing using new 525 viscosity refrigerant oil.
4. Install the switch (2) into the switch cavity until the switch bottoms in the cavity.
5. Install the A/C high pressure switch snap ring using the J 5403 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) . Ensure that the high point of the curved sides is adjacent to the switch housing. Ensure that the snap ring is properly seated in the switch cavity retaining groove.
6. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
7. Leak test the fittings of the components using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Disconnect the low pressure switch electrical connector (2).
2. Remove the low pressure switch (1) from the accumulator.
3. Remove the O-ring seal.

1. Install the new O-ring seal to the switch. Refer to «O-Ring Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Install the A/C low pressure switch (1) to the accumulator. Tighten: Tighten the switch to 4 N.m (35 lb in).
3. Connect the low pressure switch electrical connector (2).
4. Leak test the fittings of the component using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Recover the refrigerant from the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Remove the grille. Refer to «Grille Replacement (Uplevel)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) or «Grille Replacement (Base)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) in Exterior Trim.
3. Remove the discharge hose retaining nut (2).
4. Remove the discharge hose from the condenser.
5. Remove the evaporator hose retaining nut (1).
6. Remove the evaporator hose from the condenser.
7. Disconnect the electrical connector from the outside air temperature sensor (1).
8. Remove the outside air temperature bracket bolt (1).
9. Remove the bracket.
10. Remove the sealing washers from the hoses.
11. Remove the condenser retaining bolts (3).
12. Remove the condenser (2).
13. Cap off the condenser fittings.

1. If replacing condenser, add the specified amount of PAG oil directly into the condenser. Refer to «Refrigerant System Capacities»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-system-capacities) .
2. Remove the plugs from the condenser fittings.
3. Install new sealing washers. Refer to «Sealing Washer Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
4. Install the condenser.
5. Install the condenser retaining bolts (3). Tighten: Tighten the bolts to 9 N.m (80 lb in).
6. Install the outside air temperature bracket.
7. Install the outside air temperature bracket bolt (1).
8. Connect the outside air temperature sensor electrical connector to the sensor (1).
9. Install the evaporator hose to the condenser.
10. Install the evaporator hose retaining nut (1). Tighten: Tighten the nut to 16 N.m (12 lb ft).
11. Install the discharge hose to the condenser.
12. Install the discharge hose nut (2). Tighten: Tighten the nut to 16 N.m (12 lb ft).
13. Install the grille. Refer to «Grille Replacement (Uplevel)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) or «Grille Replacement (Base)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) in Exterior Trim.
14. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
15. Leak test the fittings of the component using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Recover the refrigerant from the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Remove the coolant reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
3. Disconnect the electrical connector (2) from A/C low pressure sensor (1).
4. Remove the evaporator outlet hose retaining nut (3) from the accumulator.
5. Remove the compressor inlet hose retaining nut (1).
6. Remove the retaining screw (4) from the accumulator retaining bracket (2).
7. Remove the accumulator (1).
8. Remove the sealing washers.

1. If replacing the accumulator add the specified amount of PAG oil directly into the accumulator. Refer to «Refrigerant System Capacities»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-system-capacities) .
2. Install the accumulator (1).
3. Install the screw (4) to the accumulator retaining bracket (2). Tighten: Tighten the screw to 9 N.m (80 lb in).
4. Connect the low pressure sensor electrical connector (1).
5. Install new sealing washers. Refer to «Sealing Washer Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
6. Install the evaporator outlet hose.
7. Install the evaporator outlet hose retaining nut (1) to the accumulator. Tighten: Tighten the nut to 16 N.m (12 lb ft).
8. Install the compressor inlet hose.
9. Install the compressor inlet hose retaining nut (2) to the accumulator. Tighten: Tighten the nut to 16 N.m (12 lb ft).
10. Install the coolant reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
11. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
12. Leak test the fittings of the component using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Recover the refrigerant from the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Disconnect the low pressure sensor electrical connector (2).
4. Disconnect the blower motor assembly electrical connector.
5. Disconnect the blower motor resistor assembly electrical connector.
6. Remove the retaining nut (1) from the evaporator inlet tube.
7. Remove the evaporator inlet tube retaining screw.
8. Remove the evaporator inlet tube from the evaporator.
9. Remove the O-ring seal.
10. Remove the retaining nut (1) from the accumulator.
11. Remove the accumulator from the evaporator.
12. Remove the O-ring seal.
13. Remove the blower module assembly screws.
14. Remove the blower module assembly.
15. Remove the heater assembly. Refer to «Heater Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
16. Remove the module assembly nuts (5).
17. Remove the module assembly nuts (2).
18. Remove the module from the vehicle.

1. Install the module from the vehicle.
2. Install the module assembly nuts (2). Tighten: Tighten the nuts to 6 N.m (53 lb in).
3. Install the module assembly nuts (5). Tighten: Tighten the nuts to 6 N.m (53 lb in).
4. Install the heater assembly. Refer to «Heater Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
5. Install the evaporator and blower module assembly.
6. Install the evaporator and blower module assembly retaining screws.
7. Install new O-ring seals. Refer to «O-Ring Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
8. Install the accumulator to the evaporator.
9. Install the accumulator retaining nut (1). Tighten: Tighten the nut to 18 N.m (13 lb ft).
10. Install the evaporator inlet tube to the evaporator.
11. Install the evaporator inlet tube retaining nut (1). Tighten: Tighten the nut to 16 N.m (12 lb ft).
12. Install the evaporator inlet tube retaining screw.
13. Connect the blower motor resistor assembly electrical connector.
14. Connect the blower motor assembly electrical connector.
15. Connect the low pressure sensor electrical connector (2).
16. Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
17. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
18. Leak test the fittings of the components using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

1. Remove the evaporator and blower module assembly. Refer to «Air Conditioning (A/C) Evaporator and Blower Module Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Remove the heater assembly retaining nuts (1) from the engine compartment.
3. Remove the I/P carrier. Refer to «Instrument Panel (I/P) Carrier Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
4. Disconnect the temperature actuator electrical connector.
5. Disconnect the vacuum lines from the actuators.
6. Remove the heater assembly.

1. Install the heater assembly.
2. Connect the vacuum lines to the actuators.
3. Connect the temperature actuator electrical connector.
4. Install the I/P carrier. Refer to «Instrument Panel (I/P) Carrier Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
5. Install the heater assembly retaining nuts (2) to the engine compartment. Tighten: Tighten the nuts to 6 N.m (53 lb in).
6. Install the evaporator and blower module assembly. Refer to «Air Conditioning (A/C) Evaporator and Blower Module Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Recover the refrigerant from the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Disconnect the low pressure sensor electrical connector (2).
4. Disconnect the blower motor assembly electrical connector.
5. Disconnect the blower motor resistor assembly electrical connector.
6. Remove the retaining nut (1) from the evaporator inlet tube.
7. Remove the evaporator inlet tube retaining screw.
8. Remove the evaporator inlet tube from the evaporator.
9. Remove the O-ring seal.
10. Remove the retaining nut (1) from the accumulator.
11. Remove the accumulator from the evaporator.
12. Remove the O-ring seal.
13. Remove the blower module assembly screws.
14. Remove the blower module assembly.
15. Remove the evaporator core from the evaporator and blower module assembly.

1. If replacing the evaporator core, add the specified amount of PAG oil directly into the evaporator. Refer to «Refrigerant System Capacities»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-system-capacities) .
2. Install the evaporator.
3. Install the evaporator and blower module assembly.
4. Install the evaporator and blower module assembly retaining screws.
5. Install new O-ring seals. Refer to «O-Ring Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
6. Install the accumulator to the evaporator.
7. Install the accumulator retaining nut (1). Tighten: Tighten the nut to 18 N.m (13 lb ft).
8. Install the evaporator inlet tube to the evaporator.
9. Install the evaporator inlet tube retaining nut (1). Tighten: Tighten the nut to 16 N.m (12 lb ft).
10. Install the evaporator inlet tube retaining screw.
11. Connect the blower motor resistor assembly electrical connector.
12. Connect the blower motor assembly electrical connector.
13. Connect the low pressure sensor electrical connector (2).
14. Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
15. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
16. Leak test the fittings of the components using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 38185 Hose Clamp Pliers

1. Partially drain the engine coolant. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
2. Remove the inlet heater hose clamps using the J 38185 .
3. Remove the inlet heater hose.

1. Install the inlet heater hose.
2. Install the inlet heater hose clamps using the J 38185 .
3. Fill the engine coolant. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.

J 38185 Hose Clamp Pliers

1. Partially drain the engine coolant. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L or to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-48l-53l-60l-introduction) in Engine Controls - 4.8, 5.3, and 6.0L.
3. Remove the heater hose clamps using the J 38185 .
4. Remove the outlet heater hose from the outlet radiator hose connection.
5. Remove the outlet heater hose from the heater core outlet.

1. Install the outlet heater hose to the heater core outlet.
2. Install the outlet heater hose to the outlet radiator hose connection.
3. Install the heater hose clamps using the J 38185 .
4. Fill the engine coolant. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
5. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L or to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-48l-53l-60l-introduction) in Engine Controls - 4.8, 5.3, and 6.0L.

J 38185 Hose Clamp Pliers

1. Remove the air cleaner. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L or to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-48l-53l-60l-introduction) in Engine Controls - 4.8L, 5.3L, and 6.0L.
2. Remove the upper fan shroud. Refer to «Fan Shroud Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
3. Drain the engine coolant. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
4. Remove the upper heater inlet hose clamp and the upper heater outlet hose clamp from the inlet of the coolant bypass valve (4) using the J 38185 .
5. Remove the upper heater inlet hose and the upper heater outlet hose from the outlet of the coolant bypass valve.
6. Remove the lower heater inlet hose clamp and the lower heater outlet hose clamp from the outlet of the coolant bypass valve (4) using the J 38185 .
7. Remove the lower heater inlet hose and the lower heater inlet hose from the inlet of the coolant bypass valve.
8. Remove the vacuum hose from the coolant bypass valve.

1. Install the coolant bypass valve (4).
2. Install the vacuum hose to the coolant bypass valve.
3. Install the lower heater inlet hose (5) and the lower heater outlet hose (6) to the inlet of the coolant bypass valve (4).
4. Install the lower heater inlet hose clamp and the lower heater outlet hose clamp to the inlet of the coolant bypass valve using the J 38185 .
5. Install the upper heater inlet hose and the upper heater outlet hose to the outlet of the coolant bypass valve.
6. Install the upper heater inlet hose clamp and the upper heater outlet hose clamp to the inlet of the coolant bypass valve using the J 38185 .
7. Fill the cooling system. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
8. Install the upper fan shroud. Refer to «Fan Shroud Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
9. Install the air cleaner. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L or to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-48l-53l-60l-introduction) in Engine Controls - 4.8L, 5.3L, and 6.0L.

1. Disconnect the electrical connectors from the blower motor resistor assembly.
2. Remove the blower motor resistor assembly retaining screws (1).
3. Remove the blower motor resistor assembly (2) from the evaporator and blower module assembly (3).

1. Install the blower motor resistor assembly.
2. Install the blower motor resistor assembly retaining screws (1). Tighten: Tighten the screws to 2 N.m (18 lb in).
3. Connect the electrical connectors to the blower motor resistor assembly.

1. Remove the coolant reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
2. Disconnect the blower motor electrical connector (2).
3. Remove the blower motor cooling tube (3).
4. Remove the blower motor retaining screws (1).
5. Remove the blower motor.
6. Remove the retaining clip from the fan cage (2).
7. Remove the fan cage (2) from the blower motor (3).

1. Install the fan cage (2) to the blower motor (3).
2. Install the retaining clip to the fan cage (2).
3. Install the blower motor.
4. Install the blower motor retaining screws (1). Tighten: Tighten the screws to 2 N.m (18 lb in).
5. Install the blower motor cooling tube (3).
6. Connect the blower motor electrical connector (2).
7. Install the coolant reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.

1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
2. Remove the I/P carrier. Refer to «Instrument Panel (I/P) Carrier Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
3. Remove the air distribution duct retaining screws (2).
4. Remove the retaining screws at the instrument panel.
5. Remove the air distribution duct from the instrument panel.

1. Install the air distribution duct to the instrument panel.
2. Install the air distribution duct retaining screws (2) to the instrument panel. Tighten: Tighten the screws to 4 N.m (35 lb in).
3. Install the I/P carrier. Refer to «Instrument Panel (I/P) Carrier Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
4. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

1. Use a flat blade tool to remove the instrument panel (I/P) deflector from the I/P.
2. Remove the I/P air deflector from the vehicle.

1. Align the I/P air deflector with the opening.
2. Push the I/P air deflector towards the IP opening until the deflector snaps into place.
3. Inspect the I/P air deflector for proper operation.

1. Remove the right floor outlet duct retaining screw (3) from the I/P support bracket.
2. Remove the right floor outlet duct.

1. Install the right floor outlet duct.
2. Install the right floor outlet duct screw (3) to the I/P support bracket. Tighten: Tighten the screw to 2 N.m (18 lb in).

1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
2. Remove the floor air outlet duct from the vehicle.

1. Install the floor air outlet duct to the vehicle.
2. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

1. Remove the lower air outlet duct screw (2) from the I/P bracket (1).
2. Remove the lower air outlet duct from the air distribution duct.

1. Install the lower air outlet duct (3) to the air distribution duct (4).
2. Install the lower air outlet duct screw to the I/P bracket. Tighten: Tighten the screw to 2 N.m (18 lb in).

1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
2. Remove the I/P carrier. Refer to «Instrument Panel (I/P) Carrier Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
3. Remove the windshield defrost duct retaining screws at the heater case.
4. Remove the windshield defrost duct retaining nuts at the cowl.
5. Remove the windshield defrost duct (5) from the vehicle.

1. Install the windshield defrost duct (5) to the vehicle.
2. Install the windshield defrost duct retaining nuts to the cowl. Tighten: Tighten the nuts to 4 N.m (35 lb in).
3. Install the windshield defrost duct retaining screws to the heater case. Tighten: Tighten the screws to 4 N.m (35 lb in).
4. Install the I/P carrier. Refer to «Instrument Panel (I/P) Carrier Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
5. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

1. Remove the I/P trim pad. Refer to «Trim Pad Replacement - Instrument Panel (I/P) Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
2. Remove the left window defogger duct (2) from the air distribution duct (1).

1. Install the left window defogger duct (2) to the air distribution duct (1).
2. Install the I/P trim pad. Refer to «Trim Pad Replacement - Instrument Panel (I/P) Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.

1. Remove the I/P trim pad. Refer to «Trim Pad Replacement - Instrument Panel (I/P) Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
2. Remove the right window defogger duct (1) from the air distribution duct (3).

1. Install the right window defogger duct (1) to the air distribution duct (3).
2. Install the I/P trim pad. Refer to «Trim Pad Replacement - Instrument Panel (I/P) Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.

1. Remove the heater assembly. Refer to «Heater Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
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).
5. Remove the air temperature door (1) from the heater assembly.

1. Install the air temperature door (1) to the heater assembly.
2. Install the air temperature actuator (1) to the heater assembly (2).
3. Install the air temperature actuator retaining screws. Tighten: Tighten screws to 1.9 N.m (17 lb in).
4. Connect the air temperature actuator electrical connector.
5. Install the heater assembly. Refer to «Heater Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

1. Remove the I/P carrier. Refer to «Instrument Panel (I/P) Carrier Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages, and Console.
2. Remove the heater assembly cover retaining screws.
3. Remove the heater assembly cover.
4. Disconnect the vacuum hose (1) from the defrost actuator (2).
5. Depress the clip and remove the defrost actuator (2) from the heater assembly.
6. Remove the defroster door (2) door from the heater assembly (1).

1. Install the defroster door (2) to the heater assembly (1).
2. Install the defrost actuator (2) to the heater assembly.
3. Connect the vacuum hose (1) to the defrost actuator (2).
4. Install the heater assembly cover.
5. Install the heater assembly cover retaining screws. Tighten: Tighten screws to 1.9 N.m (17 lb in).
6. Install the I/P carrier. Refer to «Instrument Panel (I/P) Carrier Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages, and Console.

1. Remove the heater assembly. Refer to «Heater Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Disconnect the vacuum hose from the lower mode actuator (2).
3. Remove the lower mode actuator (2) from the heater assembly (4).
4. Remove the linkage from the lower mode actuator (2).
5. Remove the heater assembly cover screws.
6. Remove the heater assembly cover.
7. Remove the lower mode door (1) to the heater assembly (2).

1. Install the lower mode door (1) to the heater assembly (2).
2. Install the heater assembly cover.
3. Install the heater assembly retaining screws. Tighten: Tighten screws to 1.9 N.m (17 lb in).
4. Install the linkage to the lower mode actuator (2).
5. Install the lower mode actuator (2) to the heater assembly.
6. Connect the vacuum hose to the lower mode actuator (2).
7. Install the heater assembly. Refer to «Heater Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

1. Remove the I/P carrier. Refer to «Instrument Panel (I/P) Carrier Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages, and Console.
2. Remove the heater assembly cover screws.
3. Remove the heater assembly cover.
4. Disconnect the vacuum hose from the upper mode actuator (1).
5. Remove the upper mode actuator (1) from the heater assembly (4).
6. Remove the linkage from the upper mode actuator (1).
7. Remove the upper mode door (2) from the heater module (1).

1. Install the upper mode door (2) to the heater module (1).
2. Install the heater assembly cover.
3. Install the heater assembly cover screws. Tighten: Tighten screws to 1.9 N.m (17 lb in).
4. Install the linkage to the upper mode actuator (1).
5. Install the upper mode actuator (1) to the heater assembly (4).
6. Connect the vacuum hose to the upper mode actuator (1).
7. Install the I/P carrier. Refer to «Instrument Panel (I/P) Carrier Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages, and Console.

J 39400-A Electronic Halogen Leak Detector. See Special Tools and Equipment .

1. Remove the evaporator and blower module assembly front cover (3). Refer to «Air Conditioning (A/C) Evaporator and Blower Module Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Remove the recirculation door actuator (7) and the linkage.
3. Remove the recirculation door (1) from the evaporator and blower module assembly.

1. Install the recirculation door (1) to the evaporator and blower module assembly.
2. Install the recirculation door actuator (7) and the linkage.
3. Install the evaporator and blower module assembly cover (3). Refer to «Air Conditioning (A/C) Evaporator and Blower Module Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
4. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
5. Leak test the fittings of the component replaced using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

J 38185 Hose Clamp Pliers

1. Drain the engine coolant. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
2. Remove the hose clamps using the J 38185 .
3. Remove the inlet and outlet heater hoses from the heater core.
4. Remove the screws from the heater assembly.
5. CAREFULLY open the heater core access door in order to cut the heater core access door.
6. Cut the marked section of the heater core access door.
7. Remove the retainers from the heater core.
8. Remove the heater core.

1. Install the heater core.
2. Install the heater core retainers. Tighten: Tighten the screws to 1.9 N.m (17 lb in).
3. Install the heater core access door.
4. Install the heater core access door retaining screws. Tighten: Tighten the screws to 1.9 N.m (17 lb in).
5. Install the inlet and outlet heater hoses to the heater core.
6. Install the heater hose clamps using the J 38185 .
7. Fill the engine coolant. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.

1. Remove the left rear quarter trim panels. Refer to «Trim Panel Replacement - Left Body Side»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
2. Disconnect the electrical connector from the blower motor resistor.
3. Remove the retaining screws.
4. Remove the blower motor resistor from the blower case.

1. Install the blower motor resistor into the blower case.
2. Install the retaining screws to the blower case. Tighten: Tighten the screws to 2 N.m (18 lb in).
3. Connect the electrical connector to the blower motor resistor.
4. Install the left rear quarter trim panels. Refer to «Trim Panel Replacement - Left Body Side»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

1. Remove the auxiliary HVAC module. Refer to «HVAC Module Replacement - Auxiliary»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Disconnect the electrical connectors from the auxiliary blower motor.
3. Remove the screws (1) from the auxiliary blower motor.
4. Remove the auxiliary blower motor (2).
5. Remove the retaining clip from the fan cage.
6. Remove the fan cage from the auxiliary blower motor.

1. Install the fan cage to the auxiliary blower motor.
2. Install the retaining clip to the fan cage.
3. Install the auxiliary blower motor.
4. Install the screws (1) to the auxiliary blower motor (2). Tighten: Tighten the screws to 5 N.m (44 lb in).
5. Connect the electrical connectors to the auxiliary blower motor.
6. Install the auxiliary HVAC module. Refer to «HVAC Module Replacement - Auxiliary»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

1. Remove the left rear quarter trim panel. Refer to «Trim Panel Replacement - Left Body Side»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
2. Remove the retainers from the air outlet duct.
3. Disconnect the air outlet duct from the floor vent.
4. Remove the air outlet duct from the vehicle.

1. Install the air outlet duct to the vehicle.
2. Connect the air outlet duct to the floor vent.
3. Install the retainers to the air outlet duct.
4. Install the left rear quarter trim panel. Refer to «Trim Panel Replacement - Left Body Side»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

1. Remove the left rear quarter trim panel. Refer to «Trim Panel Replacement - Left Body Side»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
2. Remove the left rear corner garnish molding. Refer to «Garnish Molding Replacement - Rear Corner»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
3. Remove the retainers from the air outlet duct.
4. Partially lower the rear headliner in order to remove the upper air outlet duct from the vent duct.
5. Disconnect the air outlet duct from the auxiliary heater.
6. Remove the air outlet duct from the vehicle.

1. Install the air outlet duct to the vehicle.
2. Connect the air outlet duct to the auxiliary heater.
3. Connect the air outlet duct to the upper headliner.
4. Install the headliner.
5. Install the retainers to the air outlet duct.
6. Install the left rear corner garnish molding. Refer to «Trim Panel Replacement - Left Body Side»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
7. Install the left rear quarter trim panel. Refer to «Garnish Molding Replacement - Rear Corner»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

1. Use a flat blade tool in order to remove the air deflector louver from the headliner.
2. Remove the air deflector louver from the vehicle.

1. Align the air deflector louver into the opening in the headliner.
2. Push the air outlet into the headliner until the deflector snaps into place.

1. Remove the auxiliary HVAC module. Refer to «HVAC Module Replacement - Auxiliary»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Remove the screws from the bottom of the auxiliary HVAC module.
3. Remove the heater core from the module.

1. Install the heater core to the module.
2. Install the screws to the bottom of the auxiliary HVAC module. Tighten: Tighten the screws to 1.9 N.m (17 lb in).
3. Install the auxiliary HVAC module. Refer to «HVAC Module Replacement - Auxiliary»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

1. Remove the evaporator core. Refer to «Evaporator Core Replacement - Auxiliary»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Gently remove the sealer packed around the thermal expansion valve (TXV).
3. Remove the clip retaining the capillary tube to the evaporator core.
4. Disconnect the evaporator tube connections from the TXV.
5. Remove the TXV from the core.

1. Install the TXV to the core.
2. Connect the evaporator tube connections to the TXV. Tighten: Tighten the tube connections to 28 N.m (21 lb ft).
3. Install the clip in order to retain the capillary tube to the evaporator core.
4. Pack sealer around the TXV in the manner found during the disassembly.
5. Install the evaporator core. Refer to «Evaporator Core Replacement - Auxiliary»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

1. Recover the refrigerant. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Drain the engine coolant. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
3. Remove the left rear quarter trim panel. Refer to «Trim Panel Replacement - Left Body Side»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
4. Remove the left rear corner garnish molding. Refer to «Garnish Molding Replacement - Rear Corner»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
5. Remove the air distribution duct upper. Refer to «Air Distribution Duct Replacement - Upper Auxiliary»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
6. Remove the air distribution duct lower. Refer to «Air Distribution Duct Replacement - Lower Auxiliary»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
7. Disconnect the electrical connectors from the auxiliary HVAC module (1).
8. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
9. Remove the cover from the underside of the auxiliary HVAC module.
10. Remove the one retaining nut in order to remove the auxiliary evaporator underbody rear tube assembly from the core.
11. Disconnect the heater lines from the underside of the auxiliary HVAC module.
12. Remove the retaining nuts from the underside of the auxiliary HVAC module.
13. Lower the vehicle.
14. Remove the auxiliary HVAC module.

1. Install the auxiliary HVAC module.
2. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Install the retaining nuts to the underside of the auxiliary HVAC module. Tighten: Tighten the auxiliary heater retaining nuts to 10 N.m (89 lb in).
4. Connect the heater lines to the underside of the auxiliary heater.
5. Install the one retaining nut to the auxiliary evaporator underbody rear tube assembly to the core. Tighten: Tighten the nut to 28 N.m (21 lb ft).
6. Install the cover to the underside of the auxiliary HVAC module.
7. Lower the vehicle.
8. Connect the electrical connectors to the auxiliary HVAC module (1).
9. Install the air distribution duct upper. Refer to «Air Distribution Duct Replacement - Upper Auxiliary»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
10. Install the air distribution duct lower. Refer to «Air Distribution Duct Replacement - Lower Auxiliary»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
11. Install the left rear corner garnish molding. Refer to «Garnish Molding Replacement - Rear Corner»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
12. Install the left rear quarter trim panel. Refer to «Trim Panel Replacement - Left Body Side»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
13. Evacuate and recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
14. Fill the engine coolant. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.

J 39400-A Halogen Leak Detector. See Special Tools and Equipment .

1. Remove the auxiliary HVAC module. Refer to «HVAC Module Replacement - Auxiliary»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Remove the screws from the auxiliary HVAC module.
3. Separate the case halves.
4. Remove the evaporator core seal.
5. Remove the evaporator core from the auxiliary HVAC module.
6. Inspect the gaskets and the seals for damage.
7. Replace the gaskets and the seals.

1. Add Refrigerant to the evaporator. Refer to «Refrigerant System Capacities»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-system-capacities) .
2. Install the evaporator core to the auxiliary HVAC module.
3. Install the evaporator core seal.
4. Reassemble the case halves.
5. Install the auxiliary HVAC module screws. Tighten: Tighten the screws to 2 N.m (16 lb in).
6. Install the auxiliary HVAC module. Refer to «HVAC Module Replacement - Auxiliary»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
7. Leak test the fittings using the J 39400-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

1. Remove the body side rear trim panel. Refer to «Trim Panel Replacement - Left Body Side»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) .
2. Pull upward to remove the blower motor relay from the connector.
3. Remove the blower motor relay.

1. Install the blower motor relay.
2. Push downward to install the blower motor relay to the connector. Make sure the relay is fully seated in the connector.
3. Install the body side rear trim panel. Refer to «Trim Panel Replacement - Left Body Side»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) .

J 41425 A/C Line Repair Kit. See Special Tools and Equipment .

Do not service the rear A/C or heater lines as a complete unit. Service the rear A/C or heater lines as a sectional repair.

You can obtain the various sections of line through GMSPO.

Use the J 41425 when any of the following actions damage the rear A/C or heater lines. See Special Tools and Equipment .

1. Rub-through
2. Collision damage
3. Leakage in the system

Minimum Tube Length Required Table

Follow the Straight Line Repair procedure in order to repair line damage in a straight section of line.

Follow the Line Sectioning Repair procedure in order to repair any damage in a bend area. Do not repair the rear A/C or heater lines in a bend area, replace the lines. Maintaining the original line shape will prevent vibrations and rub-through.

Heater and Air Conditioning (A/C) Pipe Repair - Auxiliary

Straight Line Repair

1. Recover the refrigerant, if repairing the A/C lines. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Drain the coolant, if repairing the heater lines. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Locate the area that requires repair.
5. Obtain a length of replacement line to make the repair.
6. Use a tubing cutter in order to cut and remove the section of damaged line.
7. Use a tubing cutter in order to cut the replacement line to length.
8. Use the cleaning pad from the J 41425 in order to clean any burrs or grease from the line ends. Be sure to clean at least 19 mm (0.75 in) from the line ends. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
9. Use the LOK prep sealant in order to prep the line ends.
10. Apply one drop of the J 41425-3 sealing compound to the outside of each end of the line.
11. Insert the line ends into the LOK fitting.
12. Rotate the LOK fitting one complete turn in order to evenly distribute the sealing compound around the lines.
13. Install the correct LOK fitting jaws into the J 41425-1 tool.
14. Install the J 41425-1 tool over the LOK connectors. Verify that the LOK connector ends are positioned in the counter bores of the jaws.
15. Tighten the forcing screw of the J 41425-1 tool. When fully seated, the LOK connector collars will bottom out on the center shoulder of the LOK fitting.
16. Loosen the forcing screw and remove the J 41425-1 tool from the repaired line.
17. Repeat Step 8 through Step 16 to repair the other end of the line.
18. Verify that the LOK fittings are correctly installed.
19. Lower the vehicle.
20. Refill the coolant, if drained. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
21. Evacuate and recharge the refrigerant, if repairing the A/C lines. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .

Line Sectioning Repair

1. Recover the refrigerant, if repairing the A/C lines. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .
2. Drain the coolant, if repairing the heater lines. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Obtain a new A/C or heater line for sectioning.
5. Scribe a mark on the line that will be sectioned.
6. Use a tubing cutter in order to cut the line or lines being replaced.
7. Remove the section of line being replaced from the vehicle.
8. Install the replacement line to the vehicle.
9. Use a tubing cutter in order to cut the replacement line to length.
10. Use the cleaning pad from the J 41425 in order to clean any burrs or grease. Be sure to clean at least 19 mm (0.75 in) from the A/C line. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
11. Use the LOK prep sealant in order to prep the A/C or heater line.
12. Apply one drop of the J 41425-3 sealing compound to the outside of each line end.
13. Insert the line ends into the LOK fitting.
14. Rotate the LOK fitting one complete turn in order to evenly distribute the sealing compound around the lines.
15. Install the correct LOK fitting jaws into the J 41425-1 tool.
16. Install the J 41425-1 tool over the LOK connectors. Verify that the LOK connector ends are positioned in the counter bores of the jaws.
17. Hold the tool body with a 3/8" breaker bar. Turn the forcing screw until both of the connector collars bottom on the center shoulder of the LOK fitting.
18. Loosen the forcing screw. Remove the tool from the repaired line.
19. Verify that the LOK fitting is correctly installed.
20. Lower the vehicle.
21. Refill the coolant, if drained. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
22. Evacuate and recharge the refrigerant, if repairing the A/C lines. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) .

Special Tools

Special Tools Illustration Tool Number/ Description J 5403 Snap Ring Pliers J 9553-01 O-Ring Remover J 26549-E Orifice Tube Remover and Installer J 38185 Hose Clamp Pliers J 39400-A Halogen Leak Detector J 41425 A/C Line Repair Kit J 41447 R-134a A/C Tracer Dye Box of 24 J 42220 Universal 12V Leak Detection Lamp J 43600 ACR 2000 Refrigerant Station J 43872 Fluorescent Dye Cleaner J 45037 A/C Oil Injector J 45268 Flush Adapter Kit J 46297 A/C Dye Injector Kit J 46297-12 Replacement Dye Cartridges

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

Scheme 11

Scheme 12

Scheme 13

Scheme 14

See also:
• Symptoms - HVAC Systems - Manual
• Air Delivery Description and Operation
• Air Temperature Description and Operation
• Moving Parts and Hot Surfaces Caution
• Cooling System Description and Operation
• Engine Fails To Reach Normal Operating Temperature
• Air Delivery Improper
• Drive Belt Excessive Wear Diagnosis
• Drive Belt Tensioner Diagnosis
• Drive Belt Replacement - Air Conditioning
• Vibration Analysis - Engine
• Instrument Panel (I/P) Carrier Replacement
• Loss of Coolant
• Fluid Leak Diagnosis
• Fluid Leak Diagnosis
• Power Steering Fluid Leaks
• Lifting and Jacking the Vehicle
• Air Cleaner Assembly Replacement
• Fastener Notice
• Grille Replacement (Uplevel)
• Headlamp Capsule Replacement
• Engine Cover Replacement
• Air Cleaner Assembly Replacement
• Special Tools and Equipment
• Refrigerant Recovery and Recharging
• Leak Testing
• Air Conditioning (A/C) Diagnostics - Pressure Zone A
• Air Conditioning (A/C) System Performance Test
• Flushing
• Refrigerant System Capacities
• Expansion (Orifice) Tube Replacement
• Heating Performance Diagnostic