Test Description

WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. 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.

2: This step determines if the HVAC door actuator is stalled.
5: This step applies control circuit voltages to the input of the HVAC door actuator.

DTC B0248, B0263, B0268, B0408, or B0418

Step	Action	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 - Automatic
2	Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the appropriate HVAC door actuator ON and OFF while observing the corresponding Door Actual parameter. Does the scan tool indicate that the value of the appropriate Door Actual parameter changes?	Go to Diagnostic Aids	Go to Step 3
3	Disconnect the appropriate HVAC door actuator. Probe the ignition 3 voltage circuit of the appropriate HVAC door actuator with a test lamp connected to a good ground. Does the test lamp illuminate?	Go to Step 4	Go to Step 10
4	Measure the voltage on the appropriate HVAC door actuator control circuit. Does the voltage measure near 2.5 V?	Go to Step 5	Go to Step 7
5	Connect the HVAC door actuator. Observe the appropriate HVAC door actuator drive shaft. Connect a 3 amp fused jumper wire between the appropriate door control circuit and the low reference circuit of the HVAC door actuator. Disconnect the fused jumper wire. Connect a 3 amp fused jumper wire between the appropriate door control circuit and the 5 volt reference circuit of the HVAC door actuator. Does the drive shaft of the appropriate HVAC door actuator rotate?	Go to Step 9	Go to Step 6
6	Inspect the appropriate door and the door actuator for the following conditions: A misaligned door actuator. Binding linkages A binding door An obstruction that prevents the HVAC door actuator from operating within the full range of motion Did you find and correct the condition?	Go to Step 13	Go to Step 8
7	Test the appropriate HVAC door control circuit for an open, short to ground and a short to voltage. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?	Go to Step 13	Go to Step 9
8	Inspect for poor connections at the harness connector of the appropriate HVAC door 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 13	Go to Step 11
9	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 13	Go to Step 12
10	Repair the ignition 3 voltage circuit of the appropriate HVAC door actuator. Refer to WIRING REPAIRS in Wiring Systems. Did you complete the repair?	Go to Step 13	-
11	IMPORTANT: Perform the calibration procedure for HVAC door actuators. Replace the appropriate HVAC door actuator. Refer to the appropriate replacement procedure: Recirculation Actuator Replacement Mode Actuator Replacement Defroster Actuator Replacement Air Temperature Actuator Replacement - Right Air Temperature Actuator Replacement - Left Did you complete the replacement?	Go to Step 13	-
12	Replace the HVAC control module. Refer to HVAC Control Module Replacement . Did you complete the replacement?	Go to Step 13	-
13	Use the scan tool in order to clear the DTCs. Operate the vehicle according to the Conditions for Running in the DTC as specified in the supporting text. Does the DTC set again?	Go to Step 2	System OK