GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 2000 🢒 Intrigue 🢒 Body and Accessories 🢒 Stationary Windows 🢒 Rear Window Defogger Inoperative

Step

Action

Value(s)

Yes

No

1

Were you sent here by the Symptoms Table?

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Go to Step 2

Go to Symptoms

2
  1. Turn the ignition switch to the RUN position.
  2. Press and release the rear defogger switch.
  3. Observe if the defogger indicator turns ON.

Does the defogger indicator turn ON?

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Go to Step 3

Go to Step 16

3
  1. Remove the rear window defogger relay.
  2. Use a test lamp in order to backprobe the rear window defogger relay harness connector between terminals A2 and C1.

Does the test lamp light?

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Go to Step 4

Go to Step 9

4

Use a test lamp in order to backprobe the rear window defogger relay harness connector between terminal C2 and ground.

Does the test lamp light?

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Go to Step 5

Go to Step 8

5

Important: Press and release the rear defogger switch again if the rear defogger ON indicator turns OFF before the test is complete.

Use a test lamp to backprobe the rear window defogger relay harness connector between terminals C 2 and A 1.

Does the test lamp light?

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Go to Step 6

Go to Step 7

6

Inspect the defogger for loose terminals at the relay connector and repair if found. If no loose connections are found, replace the defogger relay.

Is the repair complete?

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Go to Step 25

Go To Step 7

7

Repair a poor connection or an open in CKT 292 (LT BLU). Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 25

Go To Step 24

8

Repair a poor connection or an open in CKT 41 (BRN) between the rear window defogger relay harness connector terminal C2 and the fuse block terminal D10. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 25

Go To Step 9

9

Important: Press and release the rear defogger switch again if the rear defogger indicator turns OFF before the test is complete.

Use a test lamp in order to backprobe the rear window defogger relay harness connector between terminal A 2 and ground.

Does the test lamp light?

--

Go to Step 10

Go to Step 15

10

Important: Press and release the rear defogger switch again if the rear defogger indicator turns OFF before the test is complete.

Use a test lamp in order to backprobe the rear defogger grid harness connector between CKT 293 (PPL) and CKT 850 (BLK).

Does the test lamp light ?

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Go to Step 11

Go to Step 12

11

Repair the rear defogger grid. Refer to Defogger Grid Lines Diagnosis .

Is the repair complete?

--

Go to Step 25

Go To Step 12

12

Important: Press and release the rear defogger switch again if the rear defogger indicator turns OFF before the test is complete.

Use a test lamp in order to backprobe the rear defogger grid harness connector between CKT 293 (PPL) and ground.

Does the test lamp light?

--

Go to Step 13

Go to Step 14

13

Repair a poor connection or an open in CKT 850 (BLK) between the rear defogger grid and G301. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 25

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14

Repair a poor connection or an open in CKT 293 (PPL) between the rear window defogger relay connector terminal C1 and the rear defogger grid connector. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 25

Go To Step 15

15

Repair a poor connection or an open in CKT 1040 (ORN) between the fuse block terminal A2 and the rear window defogger relay harness connector terminal A2. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 25

Go To Step 16

16

Inspect fuse 4 in the fuse block for an open.

Is the fuse open?

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Go to Step 17

Go to Step 18

17

Repair the short to ground in CKT 41 (BRN). Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 25

Go To Step 18

18
  1. Turn the ignition switch to the RUN position.
  2. Use a test lamp in order to backprobe the heater-A/C control connector C2 terminals B7 and B8.

Does the test lamp light?

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Go to Step 19

Go to Step 21

19
  1. Press and release the rear defogger switch.
  2. Use a test lamp in order to backprobe between the heater-A/C control connector C2 terminal B2 and ground.

Does the test lamp light?

--

Go to Step 20

Go to Step 24

20

Repair a short to B+ in CKT 292 (LT BLU). Refer to Testing for a Short to Voltage and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 25

Go To Step 21

21
  1. Use a test lamp in order to backprobe between the heater-A/C control harness connector C2 terminal B7 and ground.
  2. Retest the system.

Does the test lamp light?

--

Go to Step 22

Go to Step 23

22

Repair a poor connection or an open in CKT 150 (BLK) between the heater-A/C control harness connector C2 terminal B7 and G205. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 25

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23

Repair a poor connection or an open in CKT 41 (BRN) between the fuse block terminal D10 and the heater-A/C control harness connector C2 terminal B7. Refer to Testing for a Short to Voltage and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 25

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24

Replace the heater-A/C control. Refer to one of the following procedures:

    •  Control Assembly Replacement for the manual HVAC system
    •  Control Assembly Replacement for the Automatic HVAC system.

Is the repair complete?

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Go to Step 25

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25

Verify that the system operates properly.

Does the system operate properly?

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System OK

Go to Symptoms