For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The blower motor is ON while the HVAC control is in the OFF position.
1 | Did you perform the HVAC Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - HVAC Systems - Automatic
2 |

1. Turn ON the ignition, with the engine OFF.
2. Turn OFF the HVAC controls.

Is the blower motor OFF?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3 | Disconnect the HVAC control module. Does the blower motor continue to operate? | Go to Step 4 | Go to Step 7
4 | Inspect or test the blower motor control circuit between the blower motor and the blower motor control processor for a short to ground, short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 5
5 | Test the blower motor speed request signal circuit between the HVAC control module and blower motor control processor for 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 6
6 | 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 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 | Replace the blower motor control processor. Refer to Blower Motor Control Processor 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 Module Replacement in Body Control System. Did you complete the replacement? | Go to Step 10 | --
10 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3