GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Engine Cooling Schematics .

Connector End View Reference: Component Connector End Views .

DEFINITION: One or both engine cooling fan motors run continuously in high or low speed.

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go To Diagnostic System Check - Vehicle

2

Ignition ON, engine OFF.

Are both cooling fans operating at low speed?

Go to Step 4

Go to Step 3

3

Is the left cooling fan operating at high speed?

Go to Step 5

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

4

Remove the low speed fan relay.

Did the fans turn OFF?

Go to Step 6

Repair the cooling fan motor supply voltage circuit of the right cooling fan for a short to voltage. Refer to Wiring Repairs .

5

Remove the high speed fan relay.

Did the left cooling fan turn OFF?

Go to Step 7

Repair the cooling fan motor supply voltage circuit of the left cooling fan for a short to voltage. Refer to Wiring Repairs .

6

Inspect for poor connections at the low speed fan relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

System OK

Replace the low speed fan relay.

7

Inspect for poor connections at the high speed fan relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

System OK

Replace the high speed fan relay.