GM Service Manual Online
For 1990-2009 cars only

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Action

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Schematic Reference:  Radiator Shutter Schematics

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

1

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

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 below 90.6°C (195°F).

Are the radiator shutters closed?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Remove the ignition 1 relay.
  3. Turn ON the ignition.
  4. Probe the ignition 1 relay ignition voltage supply circuit with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 4

4

Repair the ignition 1 relay ignition voltage supply circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 20

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5

Connect a test lamp between the ignition 1 relay ignition voltage supply circuit and the ground circuit of the ignition 1 relay coil.

Does the test lamp illuminate?

Go to Step 7

Go to Step 6

6

Repair the ground circuit of the ignition 1 relay coil. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 20

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7

Probe the Ignition 1 battery positive voltage supply circuit with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 9

Go to Step 8

8

Repair the battery positive voltage supply circuit of the ignition 1 relay.

Did you complete the repair?

Go to Step 20

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9

Connect a fused jumper wire between the battery positive voltage supply circuit of the ignition 1 relay and the radiator shutter control valve voltage supply circuit.

Are the radiator shutters closed?

Go to Step 14

Go to Step 10

10

Test the radiator control valve voltage supply circuit for an open, short to ground, or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 20

Go to Step 11

11

  1. Leave the fused jumper in place of the ignition 1 relay.
  2. Turn OFF the ignition.
  3. Disconnect the radiator shutter/engine coolant temperature (ECT) switch.
  4. Connect a fused jumper wire from the radiator shutter/engine coolant temperature (ECT) switch signal circuit to the (ECT) switch ground circuit at the connector.

Are the radiator shutters closed?

Go to Step 15

Go to Step 12

12

Test the radiator shutter/engine coolant temperature (ECT) switch signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 20

Go to Step 13

13

Test the ground circuit of the radiator shutter/engine coolant temperature (ECT) switch for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 20

Go to Step 16

14

Inspect for loose or poor connections at the ignition 1 relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs

Did you find and correct the condition?

Go to Step 20

Go to Step 17

15

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

Did you find and correct the condition?

Go to Step 20

Go to Step 18

16

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

Did you find and correct the condition?

Go to Step 20

Go to Step 19

17

Replace the ignition 1 relay.

Did you complete the replacement?

Go to Step 20

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18

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

Did you complete the replacement?

Go to Step 20

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19

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

Did you complete the replacement?

Go to Step 20

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20

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2