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

Step

Action

Normal Result(s)

Abnormal Result(s)*

1
  1. Turn the ignition switch off.
  2. Turn the ignition switch on.
    • Defogger ON indicator is off.
    • Defoggers are off.
    • Defogger Inop - Rear Window, Indicator Lamp On
    • Defoggers - Rear Window Inoperative, Rearview Mirrors Operate

2
  1. Press and release the defogger switch one time.
  2. Wait approximately 11 minutes.
    • Defogger ON indicator comes on.
    • Defoggers come on.
    • After approximately 10 minutes, both the defogger ON indicator and the defoggers turn off.
    • Defogger Lamp Switch Inoperative - Rear Window
    • Defoggers - Rear Window Inoperative, Rearview Mirrors Operate

3
  1. Press and release the Defogger switch one time.
  2. Wait approximately 6 minutes.
    • Defogger ON indicator comes on.
    • Defoggers come on.
    • After approximately 5 minutes, both the defogger ON indicator and the defoggers turn off.
    • Defogger Lamp Switch Inoperative - Rear Window
    • Defoggers - Rear Window Inoperative, All Windows Inoperative
    • Defoggers - Rear Window Inoperative, Rearview Mirrors Operate

4
  1. Press and release the defogger switch one time.
  2. Wait approximately 15 seconds.
  3. Press and release the defogger switch a second time, before time-out occurs.
    • Defogger ON indicator comes on and the defoggers come on.
    • When switch is pressed the second time, both the defogger ON indicator and the defoggers turn off immediately.

Defoggers - Rear Window Inoperative, All Defoggers Inoperative

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