GM Service Manual Online
For 1990-2009 cars only

The rear window defogger system consists of a tinted window that has a number of horizontal ceramic silver compound element lines and consists of two vertical bus bars baked into the inside surface during the window forming operation. The feed wire or terminal is soldered to the bus bar on the left side. The ground wire or terminal is soldered to the bus bar on the right side.

Under some conditions the heat from the window may not be detected by a finger touch. The following conditions vary the length of time required to remove the interior fog from the rear window:

    • Varies with conditions such as the vehicle speed.
    • Varies with conditions such as the outside window temperature.
    • Varies with conditions such as the atmospheric pressure.
    • Varies with conditions such as the number of passengers.

This system is operated from the heater A/C control. The heater A/C control has an automatic timer built in. The timer operates for 5 to 10 minutes, then automatically turns off. The system can be turned off during this operation period by pressing the rear window defogger switch or by turning the ignition switch to OFF.