GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

1

Did you review the Air Delivery Description and Operation and the Air Temperature Description and Operation perform the necessary inspections?

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

2

Operate the blower motor at each speed.

Does the blower motor operate when turned to the OFF position?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

3

Remove the heater relay from the right instrument panel junction block.

Does the blower motor run?

Go to Step 4

Go to Step 5

4

Repair the short to voltage in the blower motor supply voltage circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 9

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5

Test that the heater relay is open between terminals 3 and 5 and that there is continuity between terminals 3 and 4.

Did the relay test OK?

Go to Step 6

Go to Step 7

6

Test the heater relay control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 8

7

Replace the heater relay. Refer to Blower Motor Relay Replacement .

Did you complete the replacement?

Go to Step 9

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8

Replace the blower switch. Refer to Blower Switch Replacement .

Did you complete the replacement?

Go to Step 9

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9

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3