Test Description

WARNING: This page is about a different car, the 2004 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.

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

3: This step drives the actuator in one direction. The actuator shaft will not move if the actuator door is already in the position you are attempting to drive it to.
4: This step drives the actuator in the opposite direction.

DTC B0424, B3748, or B3749

Step	Action	Values	Yes	No
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views
1	Did you perform the HVAC Diagnostic System Check?	-	Go to Step 2	Go to Diagnostic System Check - HVAC Systems - Manual
2	Test the appropriate door control A circuit and the appropriate door control B circuit for an open, high resistance, short to ground or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 10	Go to Step 3
3	Turn OFF the ignition. Disconnect the HVAC control module. Connect a 10 amp fused jumper wire between the actuator door control A circuit of the appropriate actuator and battery positive voltage. Connect a 10 amp fused jumper wire between the actuator door control B circuit of the appropriate actuator and a good ground. Does the actuator shaft rotate?	-	Go to Step 7	Go to Step 4
4	Connect a 10 amp fused jumper wire between the actuator door control B circuit of the appropriate actuator and battery positive voltage. Connect a 10 amp fused jumper wire between the actuator door control A circuit of the appropriate actuator and a good ground. Does the actuator shaft rotate?	-	Go to Step 7	Go to Step 5
5	Inspect the appropriate door and actuator for the following conditions: A misaligned actuator. Refer to the following: Air Temperature Actuator Replacement Mode Actuator Replacement Recirculation Actuator Replacement Broken or binding linkages or actuator door An obstruction that prevents the actuator door from operating within its full range of motion Missing seals to the actuator door Misaligned seals to the actuator door Did you find and correct the condition?	-	Go to Step 10	Go to Step 6
6	Inspect for poor connections at the harness connector of the appropriate actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 10	Go to Step 8
7	Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 10	Go to Step 9
8	IMPORTANT: Perform the recalibration procedure for the appropriate actuator. Replace the appropriate actuator. Refer to the following: Air Temperature Actuator Replacement Mode Actuator Replacement Recirculation Actuator Replacement Did you complete the replacement?	-	Go to Step 10	-
9	IMPORTANT: Perform the recalibration procedure for the HVAC control module. Replace the HVAC control module. Refer to HVAC Control Assembly Replacement .Did you complete the replacement?	-	Go to Step 10	-
10	Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?	-	Go to Step 2	System OK