Blower Motor Resistor

Replace the blower motor resistor, which controls HVAC fan speeds, located in the HVAC housing on the passenger side of the vehicle.

Warnings

Tools required

Parts

• Blower motor resistor × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and set parking brake.
2. Turn ignition off and remove key.
3. Allow HVAC system to cool if recently operated (at least 10 minutes).

Procedure

1. 1

   Locate blower motor resistor
   Position yourself in the passenger footwell area. The blower motor resistor is located on the HVAC housing, typically on the right side of the housing near the blower motor itself. It is mounted to the exterior of the housing with the electrical connector facing the interior of the cabin. Use a flashlight to identify the resistor assembly and its mounting screws.
2. 2

   Disconnect electrical connector
   Locate the electrical connector attached to the blower motor resistor. Press the locking tab on the connector and pull it straight off the resistor terminals. Do not pull on the wires themselves; grip the connector body. The connector may be tight due to age and heat cycling.
3. 3

   Remove resistor mounting screws
   Remove the screws securing the blower motor resistor to the HVAC housing (verify exact count and fastener type against Viper-specific documentation). These screws thread into mounting bosses on the housing. Keep track of the screws as they are small and easily lost in the footwell area.
   Torque spec

   Resistor Screws2 Nm (1.5 lb-ft)
4. 4

   Remove resistor from housing
   Carefully pull the blower motor resistor assembly straight out from the HVAC housing. The resistor has terminals that protrude into the housing for airflow cooling. Extract it gently to avoid damaging the housing or resistor terminals. Inspect the old resistor for signs of burning, corrosion, or damaged terminals.
5. 5

   Inspect HVAC housing opening
   With the resistor removed, inspect the opening in the HVAC housing for debris, leaves, or signs of water intrusion. Check the mounting surface for cracks or damage. If debris is present, carefully remove it without pushing material further into the housing. Verify that the blower motor is visible through the resistor opening and appears intact.
6. 6

   Install new resistor
   Position the new blower motor resistor with the terminals facing into the HVAC housing and the electrical connector facing outward toward the cabin. Align the resistor mounting holes with the screw bosses on the housing. Push the resistor firmly into place until it seats fully against the housing surface. The resistor should sit flush with no gaps.
7. 7

   Install mounting screws
   Thread the screws through the resistor mounting holes and into the HVAC housing bosses (verify exact count and fastener type). Tighten the screws snugly by hand until seated. Do not overtighten, as the housing is plastic and can crack. The resistor should be secure with no movement when pulled gently.
   Torque spec

   Resistor Screws2 Nm (1.5 lb-ft)
8. 8

   Reconnect electrical connector
   Push the electrical connector firmly onto the blower motor resistor terminals until the locking tab clicks into place. Tug gently on the connector to verify it is fully locked. Ensure the connector body is not hanging loose or under tension from the wiring harness.

Reassembly

1. No disassembly of other components was required for this procedure.

Verification

• Turn ignition to RUN position (engine off is acceptable).
• Set HVAC controls to various fan speed positions (Low, Medium-Low, Medium-High, High) and verify blower motor operates at each speed.
• Listen for smooth operation without surging or intermittent cutting out at any speed setting.
• Verify no burning smell emanates from the passenger footwell area during operation.
• If any speed positions do not work, turn off ignition and verify electrical connector is fully seated on resistor terminals.

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