GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Engine Cooling Schematics

Connector End View Reference: Cooling System Connector End Views

DEFINITION: The starter generator control module (SGCM) coolant fan motor does not operate.

1

Did you perform the Diagnostic System Check - Engine Cooling?

Go to Step 2

Go to Diagnostic System Check - Engine Cooling

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the SGCM coolant fan ON and OFF.

Does the SGCM coolant fan turn ON and OFF with each command?

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

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Remove the SGCM coolant fan relay.
  3. Probe the battery positive voltage circuit of the SGCM coolant fan relay switch side with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 7

4

Connect a 20 A fused jumper wire between the battery positive voltage circuit and the SGCM coolant fan motor supply voltage circuit at the coolant fan relay.

Does the coolant fan operate?

Go to Step 10

Go to Step 5

5

  1. Disconnect the SGCM coolant fan motor connector.
  2. Probe the SGCM coolant fan motor supply voltage circuit at the harness connector with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 8

6

Probe the harness connector of the SGCM coolant fan motor with a test lamp connected between the SGCM coolant fan motor supply voltage circuit and the ground circuit of the coolant fan motor.

Does the test lamp illuminate?

Go to Step 11

Go to Step 9

7

Repair the battery positive circuit of the SGCM coolant fan relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

--

8

Repair the supply voltage circuit of the SGCM coolant fan motor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

--

9

Repair the ground circuit of the SGCM coolant fan motor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

--

10

Inspect for poor connections at the SGCM coolant fan relay. 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 14

Go to Step 12

11

Inspect for poor connections at the harness connector of the SGCM coolant fan motor. 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 14

Go to Step 13

12

Replace the SGCM coolant fan relay.

Did you complete the repair?

Go to Step 14

--

13

Replace the SGCM coolant fan motor. Refer to Generator Control Module Coolant Fan Motor Replacement .

Did you complete the repair?

Go to Step 14

--

14

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2