GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 1999 🢒 Grand Prix 🢒 Body and Accessories 🢒 Stationary Windows 🢒 Defogger System Check

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

Start the engine.
    • The defogger ON indicator is off.
    • The defogger is off.

2
  1. Press and release the defogger switch 1 time.
  2. Wait approximately 11 minutes.
    • The defogger ON indicator comes on.
    • The defoggers come on.
    • The defogger ON indicator and the defogger turns off after 10 minutes.

3
  1. Press and release the defogger switch 1 time.
  2. Wait 6 minutes.
    • The defogger ON indicator comes on.
    • The defoggers come on.
    • The defogger ON indicator and the defoggers turn off after 5 minutes.

Rear Window Defogger Inoperative .

4
  1. Press and release the defogger switch 1 time.
  2. Wait approximately 15 seconds.
  3. Press and release the defogger switch a second time. This must be done before time-out occurs.
    • The defogger ON indicator comes on.
    • The defoggers come on.
    • Pressing the switch for the second time causes the defogger ON indicator and the defoggers to turn off immediately.

Rear Window Defogger Inoperative .

5
  1. Turn on the radio.
  2. Press and release the defogger switch 1 time.
  3. Wait 15 seconds.
  4. Press and release the defogger switch a second time. This must be done before time-out occurs.

The radio plays normally.

Table 4 - Defogger Causes Radio Static.

* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.