Mode Door Actuator

Replace the HVAC mode door actuator in a 2008 Dodge Viper to restore proper airflow direction control through the climate control system.

Warnings

Tools required

Parts

• HVAC mode door actuator × 1 — Mopar 68028485AA or equivalent

Preparation

1. Park vehicle on level surface and apply parking brake
2. Allow interior to cool if climate control has been running
3. Disconnect battery negative terminal and wait 2 minutes
4. Remove passenger side floor mat for improved access

Procedure

1. 1

   Remove passenger side lower dash panel
   Locate and remove the fasteners securing the lower dash panel on the passenger side. The panel is held by push clips along the top edge and screws along the bottom. Carefully release the clips using a panel tool, working from one end to the other, then remove the screws and lower the panel away from the dash.
2. 2

   Remove passenger side kick panel
   Remove the kick panel trim piece adjacent to the door opening. This panel is typically secured by 2-3 push clips. Pull firmly at the bottom edge to release the clips, then slide the panel upward and out of the dash assembly.
3. 3

   Access glove box area
   Open the glove box fully. Squeeze the sides of the glove box inward to release the stops and allow it to drop down past its normal open position. This provides improved access to the HVAC case behind the glove box area.
4. 4

   Locate mode door actuator
   Using a flashlight, identify the mode door actuator on the HVAC case. The actuator is mounted on the HVAC case behind the glove box area, accessible from the passenger side footwell. It is a small rectangular motor unit with an electrical connector and is mounted to the HVAC case with mounting screws. Note its position and the orientation of the actuator arm relative to the door linkage.
5. 5

   Disconnect actuator electrical connector
   Locate the wiring harness connector attached to the actuator. Press the locking tab on the connector and pull it straight away from the actuator. If access is restricted, you may need to reach through the opening with one hand while guiding with the other.
6. 6

   Remove actuator mounting fasteners
   Remove the screws securing the actuator to the HVAC case. The actuator is typically secured by 2-3 screws. Use a socket with extension or stubby screwdriver as needed for tight access. Keep track of these fasteners as they are specific to this application.
7. 7

   Remove actuator from HVAC case
   Carefully pull the actuator away from the HVAC case. You may need to rotate it slightly to disengage the actuator arm from the mode door linkage. Work slowly to avoid breaking the plastic door linkage inside the HVAC case. If resistance is encountered, verify the actuator arm is properly aligned with the opening in the case before pulling further.
8. 8

   Inspect mode door linkage
   With the actuator removed, use a flashlight to inspect the mode door linkage inside the HVAC case. Verify the door linkage arm is intact and moves freely through its range of motion. Check for broken plastic tabs or disconnected linkages. If the linkage is damaged, more extensive HVAC case disassembly will be required.
9. 9

   Install new actuator
   Position the new actuator so its drive arm aligns with the mode door linkage opening in the HVAC case. Rotate the actuator to match the orientation noted during removal. Gently push the actuator onto the case, ensuring the drive arm engages properly with the linkage. The actuator should seat flush against the mounting surface.
10. 10

    Secure actuator mounting fasteners
    Install the mounting screws and tighten them evenly to secure the actuator to the HVAC case. Do not overtighten as the mounting bosses are plastic and can crack. Tighten until snug and the actuator is firmly mounted without movement.
11. 11

    Connect electrical connector
    Push the wiring harness connector onto the actuator until the locking tab clicks into place. Verify the connection is secure by gently tugging on the connector.
12. 12

    Reinstall glove box
    Return the glove box to its normal position by lifting it up and pushing the sides outward to engage the stops. Close the glove box to verify proper operation.
13. 13

    Reinstall kick panel
    Position the kick panel trim piece and slide it downward into the dash assembly. Press firmly along the clip locations to seat the clips fully.
14. 14

    Reinstall lower dash panel
    Position the lower dash panel and install the mounting screws along the bottom edge. Press firmly along the top edge to engage the push clips. Verify the panel is fully seated with no gaps.
15. 15

    Calibrate and test actuator
    Reconnect the battery negative terminal. Turn the ignition to the ON position without starting the engine. Cycle through all HVAC mode positions (defrost, panel, floor, bi-level) multiple times to allow the actuator to calibrate and learn its full range of motion. Listen for smooth actuator operation without clicking or binding. Verify airflow direction changes properly for each mode setting.

Reassembly

1. Reinstall all panels in reverse order of removal
2. Ensure all trim clips are fully seated and panels are flush
3. Replace passenger floor mat

Verification

• Start engine and turn on climate control system
• Test all HVAC mode positions (defrost, panel vents, floor, bi-level) to verify proper airflow direction
• Listen for abnormal clicking or grinding from the actuator during mode changes
• Verify no air leaks from the HVAC case or loose panels
• Confirm all dash panels are secure and properly aligned

Related trouble codes on this vehicle

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