GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Engine Cooling Schematics

1

Did you perform the Engine Cooling Diagnostic System Check?

Go to Step 2

Go To Diagnostic System Check - Engine Cooling

2

Turn ON the ignition, with the engine OFF.

Does the Low Coolant Level indicator illuminate?

Go to Step 3

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

3

  1. Turn OFF the ignition.
  2. Disconnect the engine coolant level switch.
  3. Connect a 3 Amp fused jumper between the signal circuit of the engine coolant level switch and the ground circuit of the engine coolant level switch.
  4. Install a scan tool.
  5. Turn ON the ignition, with the engine OFF.
  6. Select the instrument panel cluster (IPC) inputs menu.

Does the scan tool indicate that the Low Coolant Lamp is OFF?

Go to Step 7

Go to Step 4

4

Test the ground circuit of the engine coolant level switch for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 5

5

Test the signal circuit of the engine coolant level switch for the following conditions:

    • An open
    • A short to voltage
    • A high resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 6

6

Inspect for poor connections at the harness connector of the IPC. 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 10

Go to Step 8

7

Inspect for poor connections at the harness connector of the engine coolant level switch. 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 10

Go to Step 9

8

Replace the IPC. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.

Did you complete the repair?

Go to Step 10

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9

Replace the engine coolant level switch. Refer to Radiator Surge Tank Replacement .

Did you complete the repair?

Go to Step 10

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10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2