GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Test the engine coolant heater power supply cord for an open or short to ground. Refer to Circuit Testing .

Did you find the condition?

Go to Step 3

Go to Step 4

3

Replace the engine coolant heater power supply cord. Refer to Coolant Heater Cord Replacement .

Did you complete the repair?

Go to Step 6

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4

Inspect for poor connections at the harness connector of the engine coolant heater. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find the condition?

Go to Step 6

Go to Step 5

5

Replace the engine coolant heater. Refer to Coolant Heater Replacement .

Did you complete the repair?

Go to Step 6

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6

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2