GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

  1. Disconnect the powertrain control module (PCM) connector C1.
  2. Turn the ignition switch to the RUN position.

Does the coolant temperature warning indicator light?

--

Go to Step 2

Go to Step 3

2

  1. Repair the short to ground in CKT 35.
  2. Inspect the system.

Is the symptom still present?

--

--

System OK

3

  1. Turn the ignition switch to RUN position.
  2. Connect a fused 3 amp jumper between the PCM harness.

Does the coolant temperature warning indicator light?

--

Go to Step 4

Go to Step 5

4

  1. Replace the powertrain control module. Refer to Engine Controls.
  2. Inspect the system.

Is the symptom still present?

--

--

System OK

5

  1. Inspect for a poor connection or an open in CKT 35 between the instrument cluster harness connector C1 terminal 75.
  2. If OK, replace the instrument cluster. Refer to Instrument Cluster Replacement .
  3. Inspect the system.

Is the symptom still present?

--

--

System OK