Blower Motor Inoperative

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.

Step	Action	Yes	No
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The blower motor is inoperative in all speed positions.
1	Did you perform the HVAC Diagnostic System Check?	Go to Step 2	Go to Diagnostic System Check - HVAC Systems - Automatic
2	Turn ON the ignition, with the engine OFF. Place the blower motor switch in each speed position. Does the blower motor operate in any of the speed positions?	Go to Blower Motor Malfunction	Go to Step 3
3	Turn OFF the ignition. Disconnect the blower motor connector. Turn ON the ignition, with the engine OFF. Connect a test lamp between the blower motor supply voltage circuit and the blower motor ground circuit. Place the blower motor switch in the maximum speed position. Place the air temperature switch to the warmest position. Does the test lamp illuminate?	Go to Step 10	Go to Step 4
4	Disconnect the blower motor control processor. Connect a test lamp between the battery positive voltage circuit and the ground circuit of the blower motor control processor. Does the test lamp illuminate?	Go to Step 8	Go to Step 5
5	Connect a test lamp between the battery positive voltage circuit of the blower motor control processor and a good ground. Does the test lamp illuminate?	Go to Step 7	Go to Step 6
6	Repair the battery positive voltage circuit of the blower motor control processor. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 16	-
7	Repair the ground circuit of the blower motor control processor. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 16	-
8	Connect a test lamp between the blower motor speed control circuit and the battery positive voltage circuit of the blower motor control processor. Observe the test lamp. Place the blower motor switch from the minimum speed position to the maximum speed position. Does the test lamp increase intensity when the blower speed is increased?	Go to Step 11	Go to Step 9
9	Test the blower motor speed control circuit of the blower motor control processor for an open, short to ground, or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 16	Go to Step 12
10	Inspect for poor connections at the harness connector of the blower motor. 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 16	Go to Step 13
11	Inspect for poor connections at the harness connector of the blower motor control processor. 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 16	Go to Step 14
12	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 16	Go to Step 15
13	Replace the blower motor. Refer to Blower Motor Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement?	Go to Step 16	-
14	Replace the blower motor control processor. Refer to Blower Motor Control Processor Replacement . Did you complete the replacement?	Go to Step 16	-
15	IMPORTANT: Perform the recalibration procedure for the HVAC control module. Replace the HVAC control module. Refer to HVAC Control Module Replacement .Did you complete the replacement?	Go to Step 16	-
16	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 2