GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Instrument Cluster System Check?

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Go to Step 2

Go to Instrument Cluster System Check

2

  1. Turn the ignition switch to LOCK.
  2. Disconnect the ECT sending unit connector.
  3. Connect the red lead from the J 33431-C to the ECT sending unit connector and the other lead to the ground.
  4. Set the resistance dial of the tester to 138 ohms, 52 ohms, and 10 ohms.

Does the ECT gauge indicate the appropriate readings within the specified values?

C at 138 ohms

Midpoint between C and H at 52 ohms

H at 10 ohms

Go to Step 3

Go to Step 4

3

Replace the ECT sending unit.

Is the repair complete?

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Go to Instrument Cluster System Check

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4

  1. Disconnect J 33431-C .
  2. Disconnect the instrument panel cluster assembly connector C1.
  3. Use a J 39200 digital multimeter in order to probe the instrument panel cluster assembly connector C1 from terminal 5 to the ECT sending unit connector.
  4. Measure the resistance.

Is the resistance greater than the specified value?

5.0 ohms

Go to Step 5

Go to Step 6

5

Repair the open in the YEL/WHT wire between the instrument panel cluster assembly and the ECT sending unit. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Instrument Cluster System Check

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6

Inspect for high resistance in the instrument panel cluster printed circuit.

Does high resistance exist?

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Go to Step 7

Go to Step 8

7

Repair the instrument panel cluster printed circuit.

Is the repair complete?

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Go to Instrument Cluster System Check

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8

Replace the ECT gauge.

Is the repair complete?

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Go to Instrument Cluster System Check

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