Test Description

WARNING: This page is about a different car, the 2007 Hummer H2. 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.
3: This step applies control circuit voltages to the input of the HVAC door actuator.

DTC 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 Diagnostic System Check - Vehicle?	Go to Step 2	Go to Diagnostic System Check - Vehicle
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 in the Heating and Air Conditioning Data List. 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 appropriate door control circuit at the HVAC control module and a good ground. Disconnect the fused jumper wire. Connect a 3-amp fused jumper wire between the appropriate door control circuit and the 5-volt reference circuit at the 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 . 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 . 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 . 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 . Did you complete the repair?	Go to Step 12	-
10	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 Air Temperature Actuator Replacement - Right Air Temperature Actuator Replacement - Left Did you complete the replacement?	Go to Step 12	-
11	Replace the HVAC control module. Refer to Control Module References for replacement, setup, and programming. 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 in the DTC, as specified in the supporting text. Does the DTC set again?	Go to Step 2	System OK