GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

Schematic Reference: Radiator Shutter Schematics

DEFINITION: The radiator shutters do not open when the engine coolant temperature is above 90.6°C (195°F).

1

Did you review the radiator shutter system operation and perform the necessary inspections?

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Go to Step 2

Go to Symptoms - Engine Cooling

2

  1. Turn ON the ignition, with the engine OFF.
  2. Verify that the engine coolant temperature is above 90.6°C (195°F).

Are the radiator shutters open?

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

Go to Step 3

3

Important: After unplugging the ECT switch in this step, do not plug it back in until the problem is located.

  1. Turn OFF the ignition.
  2. Disconnect the radiator shutter/engine coolant temperature (ECT) switch.
  3. Turn ON the ignition, with the ignition OFF.

Are the radiator shutters open?

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Go to Step 5

Go to Step 4

4

Test the coolant temperature signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 9

Go to Step 6

5

Inspect for loose or poor connections at the radiator shutter/engine coolant temperature (ECT) switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 9

Go to Step 7

6

Inspect for loose or poor connections at the radiator shutter valve assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 9

Go to Step 8

7

Replace the radiator shutter/engine coolant temperature (ECT) switch. Refer to Shutter Engine Coolant Temperature Sensor Replacement .

Did you complete the repair?

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Go to Step 9

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8

Replace the radiator shutter valve assembly. Refer to Shutter Valve Replacement .

Did you complete the repair?

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Go to Step 9

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9

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 2