Climate Control Module

This procedure covers removal and replacement of the climate control module (HVAC control head) located in the dashboard of a 1994-2007 Dodge Ram 2500 with the 5.9L Cummins diesel engine.

Warnings

Tools required

Parts

• Climate control module (HVAC control head) × 1 — Use OEM specification or aftermarket equivalent
• Dashboard trim panel clips (if broken) — Mopar 6503234AA or equivalent

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn ignition to OFF position and remove key
3. Disconnect negative battery cable and wait 5 minutes for airbag system capacitors to discharge
4. Allow engine to cool completely if vehicle was recently operated
5. Gather all tools and replacement parts within easy reach
6. Take photos of dashboard area and control module connections for reference during reassembly

Procedure

1. 1

   Remove dashboard bezel trim panel
   Using plastic trim removal tools, carefully pry the dashboard bezel surrounding the radio and climate control module. Start at the lower corners and work around the perimeter. Release all retaining clips gently to avoid breakage. The bezel surrounds the radio, climate controls, and extends to the instrument cluster area. Pull the bezel forward once all clips are released.
2. 2

   Remove radio (if necessary for access)
   On some model years, the radio may need to be removed for access to climate control mounting bolts. Remove the radio mounting bracket screws (verify count and size for your specific model year) securing the radio. Slide radio forward partially and disconnect antenna cable and electrical connectors from rear of radio. Set radio aside in safe location.
3. 3

   Access climate control module mounting
   With the bezel removed, the climate control module will be visible in its housing. Identify the mounting bracket screws typically located on the sides or top/bottom of the module. The number of mounting screws varies by model year; identify and remove all screws securing the module to the dash frame for your specific configuration.
4. 4

   Disconnect vacuum line (if equipped)
   For models with vacuum-operated mode doors, disconnect the vacuum harness from the rear of the control module. This is typically a single multi-port connector that pulls straight out. Note the routing of the vacuum line for reinstallation. Diesel models are less likely to have vacuum-operated HVAC controls, but check your specific configuration.
5. 5

   Label and disconnect electrical connectors
   The climate control module will have 2-4 electrical connectors depending on options (manual vs automatic climate control). Use masking tape to label each connector with its position. Press the locking tabs and disconnect all electrical connectors from the rear of the module. Some connectors may be tight due to age; work them gently to avoid breaking connector housings.
6. 6

   Disconnect cable controls (manual systems)
   If equipped with manual cable-operated temperature and mode controls, release the cable ends from the control levers. Cables typically have a clip that slides off or a small retaining tab. Note the position and routing of each cable. Note the position and routing of each cable during removal, as blend door and mode door cable locations vary by configuration; label them to ensure correct reconnection.
7. 7

   Remove climate control module mounting screws
   Remove the mounting screws securing the climate control module to the dash bracket. These are typically 8mm or 10mm screws. Keep track of any brackets, spacers, or ground wires attached to the mounting points. Store hardware in a container for reinstallation.
8. 8

   Extract climate control module
   Carefully pull the climate control module forward and out of the dashboard opening. Work it past any surrounding structure while ensuring all connectors and cables are fully disconnected. Inspect the removed module for any visible damage, burned circuits, or broken components that confirm the need for replacement.
9. 9

   Inspect and clean mounting area
   With the module removed, inspect the dash mounting bracket for any damage or loose components. Clean the mounting area of dust and debris. If cable-operated, inspect the cable routing and ensure cables move freely. Check electrical connectors for corrosion or damaged pins; clean with electrical contact cleaner if needed.
10. 10

    Position new climate control module
    Position the new or replacement climate control module in the dashboard opening. Ensure proper orientation by aligning mounting screw holes. Do not force the module into position; it should slide in with gentle pressure. Verify that no wires or cables are pinched behind the module.
11. 11

    Reconnect cable controls (manual systems)
    If equipped with cable-operated controls, reconnect each cable to its corresponding lever on the new module. Ensure cables are properly seated and retaining clips are fully engaged. Verify smooth operation by moving control levers through their full range before securing the module.
12. 12

    Reconnect electrical connectors
    Reconnect all electrical connectors to the climate control module, referencing your labels or photos. Each connector should click firmly into place. Ensure locking tabs are fully engaged. Double-check that each connector is on the correct port.
13. 13

    Reconnect vacuum line (if equipped)
    If your vehicle has vacuum-operated HVAC controls, reconnect the vacuum harness to the rear of the module. Ensure the connector is fully seated and properly routed to prevent kinking or interference with other components.
14. 14

    Secure climate control module
    Install the mounting screws to secure the climate control module to the dash bracket. Tighten screws evenly in a cross pattern to ensure even pressure. Do not overtighten, as this can crack the module housing or strip threads in the mounting bracket. These small mounting screws do not have a published torque spec; snug them by hand until seated without overtightening to avoid cracking the module housing or stripping the mounting bracket.
15. 15

    Reinstall radio and dashboard bezel
    If the radio was removed, reconnect its electrical connectors and antenna cable, then secure with mounting screws. Position the dashboard bezel over the climate control module and radio, aligning all clips with their receptacles. Press firmly around the perimeter until all clips engage with audible clicks. Ensure bezel is flush and evenly seated.

Reassembly

1. Reconnect negative battery cable and tighten battery terminal
2. Turn ignition to ON position (do not start engine) and verify climate control module illuminates
3. Test all climate control functions including fan speeds, temperature adjustment, mode selection, and air conditioning operation
4. If equipped with automatic temperature control, verify proper system initialization and self-test completion
5. Verify rear window defrost and recirculation functions operate correctly
6. Check that all dashboard lights and indicator LEDs on the control module function properly
7. Reset radio clock and presets if necessary; enter radio security code if prompted

Verification

• Start engine and verify blower motor operates at all speed settings
• Test temperature control from full cold to full heat positions and verify air temperature changes appropriately
• Cycle through all mode positions (defrost, panel, floor, bi-level) and verify proper airflow direction from correct vents
• Verify air conditioning compressor engages when AC button is pressed (compressor clutch should click and engage)
• Check that recirculation door operates when recirculation button is pressed
• Test rear defrost function and verify grid heats up
• Ensure no warning lights or error codes are present on instrument cluster related to HVAC system
• Verify all control knobs, buttons, and switches operate smoothly without binding
• Confirm dashboard bezel is secure with no rattles or loose clips

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