GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Engine Cooling Schematics

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

1

Did you perform the Engine Cooling Diagnostic System Check?

Go to Step 2

Go To Diagnostic System Check - Engine Cooling

2

Important: The cooling fan 1 relay and cooling fan 2 relay are improperly identified in the underhood fuse block. Refer to Engine Cooling Schematics for proper identification.

Turn ON the ignition, with the engine OFF.

Are one or both cooling fans ON?

Go to Step 3

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

3

Are both cooling fans running continuously?

Go to Step 5

Go to Step 4

4

Remove the cooling fan S/P relay.

Did the left cooling fan turn OFF?

Go to Step 6

Go to Step 7

5

Repair the short to voltage in the right cooling fan motor supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 8

--

6

Repair the short to voltage in the cooling fan low reference circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 8

--

7

Repair the short to voltage in the left cooling fan motor supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 8

--

8

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2