AC Evaporator

This procedure involves removing the dashboard, HVAC housing, and replacing the AC evaporator core, requiring complete refrigerant system evacuation and recharge.

Warnings

Tools required

Parts

• AC Evaporator Core × 1 — Use OEM specification
• AC O-ring kit × 1 — Use OEM specification
• Expansion valve (TXV) × 1 — Recommend replacement during evaporator service
• Orifice tube × 1 — Use OEM specification
• Receiver/drier or accumulator × 1 — Use OEM specification
• PAG oil (compatible with R134a) × 1 — GM part 12378525 or equivalent
• R134a refrigerant × 1 — Typically 2.2 lbs capacity
• Evaporator case foam seal × 1 — Use OEM specification
• Dashboard fastener assortment × 1 — Replacement clips recommended

Fluids

• ACDelco DEX-COOL (Orange) — 1 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery cable and wait minimum 2 minutes for airbag system capacitor discharge
3. Using certified AC recovery equipment, recover all refrigerant from system and verify complete recovery
4. Remove engine cover if equipped
5. Position steering wheel straight ahead and remove key from ignition
6. Remove both front seats by unbolting four bolts per seat to improve dashboard access
7. Cover seats, carpet, and windshield interior to prevent damage during dashboard removal
8. Prepare labeled bags or containers for fasteners and small parts organized by removal sequence

Procedure

1. 1

   Disconnect AC lines at firewall
   From engine bay, locate AC line connections at firewall near evaporator inlet/outlet. Disconnect both liquid and suction lines using appropriate flare nut wrenches. Immediately cap all open fittings to prevent moisture and debris entry. Remove and discard old O-rings.
2. 2

   Remove lower dash panels and covers
   Remove lower dash trim panel on driver side by removing screws and releasing clips. Remove knee bolster below steering column. Remove lower passenger side trim panels and glove box by releasing hinge pins and removing mounting screws. Disconnect electrical connectors as panels are removed.
3. 3

   Remove steering column
   Disconnect steering column electrical connectors including ignition switch, multifunction switch, and any other harnesses. Remove steering column mounting bolts (typically 4 bolts). Carefully lower and support steering column without placing strain on intermediate shaft. Mark intermediate shaft to pinion gear relationship before separating if required for additional clearance.
4. 4

   Disconnect instrument panel harnesses and HVAC controls
   Disconnect all instrument cluster electrical connectors. Remove center stack trim and radio/climate control assembly. Disconnect HVAC control cables or electrical connections depending on configuration. Disconnect all remaining electrical connectors from instrument panel including airbag connectors (if equipped), noting yellow airbag connectors require specific locking mechanisms.
5. 5

   Remove instrument panel mounting fasteners
   Locate and remove all instrument panel mounting bolts and screws. Typical locations include: both A-pillar side fasteners, upper cowl area fasteners (accessed by opening doors), center support bracket bolts, and any remaining floor mounting points. There are typically 10-14 main mounting bolts plus various screws.
6. 6

   Remove instrument panel assembly
   With all fasteners and connections removed, carefully pull instrument panel rearward from windshield area. This requires two people due to size and weight. Verify no remaining electrical connectors or fasteners are attached. Lift and remove panel from vehicle, taking care not to damage door openings or windshield. Place on protected surface.
7. 7

   Access HVAC housing and disconnect blower motor
   With dash removed, HVAC housing is now fully visible. Disconnect blower motor electrical connector. Remove blower motor mounting screws and remove blower motor assembly from housing. Set aside for reinstallation.
   Torque spec

   Blower Motor Screws8 Nm (6 lb-ft)
8. 8

   Remove HVAC housing mounting fasteners
   Disconnect any remaining vacuum lines, drain tubes, and temperature sensor connections from HVAC housing. Remove HVAC housing mounting bolts from firewall and floor brackets. Note location of different length bolts for reassembly.
   Torque spec

   Mounting Bolts34 Nm (25 lb-ft)
9. 9

   Remove HVAC housing from vehicle
   Carefully maneuver HVAC housing away from firewall studs and AC line penetrations. The housing is bulky but relatively lightweight. Remove housing from vehicle and place on clean work surface for disassembly.
10. 10

    Disassemble HVAC case and remove evaporator
    Remove case screws holding upper and lower HVAC case halves together. Carefully separate case halves taking note of foam seal locations and condition. Remove expansion valve from evaporator inlet, noting orientation. Lift evaporator core from lower case half. Remove old foam seals from case. Inspect case for debris, leaves, or water damage.
    Torque spec

    Evaporator Case Screws5 Nm (4 lb-ft)

    Expansion Valve10 Nm (7 lb-ft)
11. 11

    Install new evaporator and expansion valve
    Install new foam seals in case if provided with evaporator. Add specified amount of PAG oil to new evaporator (typically 3 oz, verify with evaporator specifications). Place new evaporator core into lower case half ensuring proper orientation with inlet/outlet aligned to case openings. Install new expansion valve with new O-rings lubricated with PAG oil to evaporator inlet.
    Torque spec

    Expansion Valve10 Nm (7 lb-ft)
12. 12

    Reassemble HVAC housing
    Position upper case half over lower half, ensuring evaporator is properly seated and all blend doors, actuators, and seals are correctly positioned. Install and tighten case screws in a cross-pattern to ensure even sealing. Verify all case openings align properly with mounting points and duct connections.
    Torque spec

    Evaporator Case Screws5 Nm (4 lb-ft)
13. 13

    Reinstall HVAC housing and blower motor
    Position HVAC housing in vehicle, aligning with firewall studs and AC line penetrations. Install mounting bolts to firewall and floor brackets, torquing to specification. Reconnect vacuum lines, temperature sensors, and drain tube. Install blower motor assembly and tighten mounting screws to specification. Reconnect blower motor electrical connector.
    Torque spec

    Mounting Bolts34 Nm (25 lb-ft)

    Blower Motor Screws8 Nm (6 lb-ft)
14. 14

    Reinstall instrument panel
    With assistance, position instrument panel into vehicle and align with mounting points. Install all mounting bolts and screws at A-pillars, upper cowl, center bracket, and floor locations, torquing fasteners appropriately. Reconnect all electrical connectors, HVAC controls, and instrument cluster connections. Ensure airbag connectors are properly locked.
15. 15

    Reinstall steering column and interior components
    Raise steering column into position, aligning intermediate shaft if separated. Install column mounting bolts and torque to specification. Reconnect all steering column electrical connectors. Reinstall knee bolster, glove box, lower trim panels, and center stack components. Install front seats and torque mounting bolts.
16. 16

    Connect AC lines at firewall
    Install new O-rings on both AC line fittings, lubricating with PAG oil. Connect liquid and suction lines at firewall evaporator connections. Torque line fittings to specification using appropriate flare nut wrenches. Ensure connections are clean and properly seated before tightening.
    Torque spec

    AC Line Fittings20 Nm (15 lb-ft)
17. 17

    Evacuate and recharge AC system
    Reconnect negative battery cable. Using certified AC service equipment, evacuate system to 29+ inches vacuum for minimum 30-45 minutes to remove all moisture. Monitor for vacuum decay to verify system integrity. If vacuum holds, recharge system with specified amount of R134a refrigerant (typically 2.2 lbs for this vehicle). Add UV dye if desired for future leak detection.

Reassembly

1. Install new receiver/drier or accumulator as AC system was opened to atmosphere
2. Torque all fasteners to specifications provided, particularly AC line fittings to prevent leaks
3. Ensure all electrical connectors are fully seated and locked, especially yellow airbag connectors
4. Verify blend door operation moves freely before final dashboard installation
5. Replace any broken trim clips identified during disassembly
6. Check that all dashboard vents, controls, and panels fit flush and operate correctly

Verification

• Start engine and verify all instrument cluster gauges, warning lights, and displays function normally
• Test all HVAC controls including temperature blend, mode selection, and fan speeds across all settings
• Verify cold air output from vents reaches appropriate temperature (typically 40-45°F at center vents)
• Check for AC refrigerant leaks at evaporator line connections using electronic leak detector
• Inspect AC system pressures: approximately 25-35 PSI low side and 200-250 PSI high side at idle with 95°F ambient (pressures vary with temperature)
• Verify no air leaks around dashboard or HVAC housing by listening for whistling at vents
• Test all steering column functions including turn signals, wipers, ignition, and tilt/telescoping operation
• Verify no airbag warning lights illuminate after reconnecting battery
• Check evaporator drain tube drips water when AC runs, confirming proper condensate drainage

Related trouble codes on this vehicle

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