Test Description

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 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: Determines if the HVAC door actuator is stalled.
3: Applies control circuit voltages to the input of the HVAC door actuator.

DTC B0248, B0263, 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 - Manual
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	Observe the appropriate HVAC door actuator drive shaft. Connect a 3 amp fused jumper wire between door control circuit at the appropriate HVAC control module and a good ground. Disconnect the fused jumper wire. Connect a 3 amp fused jumper wire between the door control circuit and the 5 volt reference circuit at the appropriate HVAC control module. Does the drive shaft of the appropriate HVAC door actuator rotate?	Go to Step 8	Go to Step 4
4	Test the door control circuit of the appropriate HVAC door actuator for a short to voltage, for a short to ground, or for an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 12	Go to Step 5
5	Turn OFF the ignition. Disconnect the fused jumper wire. Disconnect the appropriate HVAC door actuator. Turn ON the ignition, with the engine OFF. Probe the ignition 3 voltage circuit of the appropriate HVAC door actuator with a test lamp that is connected to ground. Does the test lamp illuminate?	Go to Step 6	Go to Step 9
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 12	Go to Step 7
7	Inspect for poor connections at the harness connector of the appropriate HVAC door actuator. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 12	Go to Step 10
8	Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 12	Go to Step 11
9	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 12	-
10	IMPORTANT: Perform the calibration procedure for HVAC door actuators. Replace the HVAC door actuator. Refer to the appropriate replacement procedure: Air Temperature Actuator Replacement - Right Air Temperature Actuator Replacement - Left Defroster Actuator Replacement Mode Actuator Replacement Did you complete the replacement?	Go to Step 12	-
11	Replace the HVAC control module. Refer to HVAC Control Module Replacement . Did you complete the replacement?	Go to Step 12	-
12	Use the scan tool in order to clear the DTCs. Operate the vehicle according to the Conditions for Running the DTC as specified in the supporting text. Does the DTC set again?	Go to Step 2	System OK