GM Service Manual Online
For 1990-2009 cars only

Object Number: 142229  Size: MF

Step

Action

Value(s)

Yes

No

DEFINITION: The rear defogger does not operate when the rear defogger button is pressed.

1

Were you sent here from the defogger system check?

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Go to Step 2

Go to Defogger System Check .

2

  1. Install the scan tool.
  2. Turn the ignition on.
  3. Using the scan tool, display special functions Rear Integration Module (RIM). Select the rear defogger relay.
  4. Press the defogger button on.

Does the request for the rear defogger relay change from ON to OFF?

--

Go to Step 3

Go to Step 6

3

Using the scan tool, command the defogger relay on.

Did the relay click?

--

Go to Step 4

Go to Step 7

4

Measure the voltage at terminal A of the rear window defogger.

Is the voltage above the specified value?

10.5 V

Go to Step 9

Go to Step 5

5

Measure the voltage to terminal C5 connector C3 of the rear junction block and ground.

Is the voltage above the specified value?

10.5 V

Go to Step 10

Go to Step 12

6

Inspect for a loose connection at the Rear Integration Module (RIM). If terminal contact is OK, Replace the RIM. Refer to Body Control Module Replacement in Body Control Systems.

Is the repair complete?

--

Go to Step 13

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7

Measure resistance of the Rear Defog relay windings.

Is resistance within the specified value?

70-90 ohms

Go to Step 8

Go to Step 11

8

Repair open in CKT 193 (WHT).

Is the repair complete?

--

Go to Step 12

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9

Repair the rear window defogger ground.

Is the repair complete?

--

Go to Step 12

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10

Repair open in CKT 293 (PPL).

Is the repair complete?

--

Go to Step 12

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11

Replace the RR DEFOG relay?

Is the repair complete?

--

Go to Step 12

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12

Use a known good relay. Is the voltage at terminal 5, connector C3 of the Rear Junction Block below the specified value?

10.5 V

Go to Step 13

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13

Replace the Rear Junction Block.

Is the repair complete?

--

Go to step 14

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14

Confirm proper operation of the rear window defogger.

Is the rear defogger operating correctly?

--

System OK

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