For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: HVAC Schematics . Connector End View Reference: Component Connector End Views . DEFINITION: The blower motor is inoperative in all speed positions.
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle .
2 |

1. Turn ON the ignition, with the engine OFF.
2. Place the blower motor switch in each speed position.

Does the blower motor operate in any speed position?

Go to Blower Motor Malfunction .

Go to Step 3

3 |

1. Turn OFF the ignition.
2. Disconnect the blower motor.
3. Connect a test lamp between the blower motor supply voltage circuit and the blower motor control circuit.
4. Turn ON the ignition, with the engine OFF.
5. Place the blower motor switch in each speed position.

Does the test lamp illuminate in any speed position?

Go to Step 10

Go to Step 4

4 | Test the blower motor supply voltage circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 5
5 | Test the blower motor control circuit for an open or high resistance between the blower motor and X124. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 6
6 |

1. Turn OFF the ignition.
2. Connect the blower motor.
3. HVAC control module.
4. Turn ON the ignition, with the engine OFF.
5. Place the blower motor switch in each speed position.

Does the blower motor operate in any speed position?

Go to Step 11

Go to Step 7

7 | Check for any serial data codes or faults Did you find a fault? | Go to Step 8 | Go to Step 9
8 | Test GMLAN wiring. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 9
9 | Important: The blower motor switch is part of the infotainment unit facia and communicates via GMLAN Test the blower motor switch control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 12
10 | Inspect for poor connections at the blower motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 13
11 | Inspect for poor connections at the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 14
12 | Important: The blower motor switch is part of the infotainment unit facia and communicates via GMLAN Inspect for poor connections at the infotainment unit facia . Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

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 . Did you complete the replacement? | Go to Step 16 | --
14 | Replace the HVAC control module. Refer to HVAC Control Module Replacement . Did you complete the replacement? | Go to Step 16 | --
15 | Replace the blower switch. Refer to Radio 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