GM Service Manual Online
For 1990-2009 cars only

The optional rear window defogger system consists of the following components:

    • A tinted window containing a number of horizontal ceramic compound element lines
    • Two vertical bus bars
        The bus bars are baked into the inside of the glass when the glass is formed.

The feed wire or terminal is soldered to the bus bar on the left side.

The ground wire or the terminal is soldered to the busbar on the right.

The system operates on 12 volts.

Under certain conditions, heat from the window may not be detected by touch.

The following conditions determine the length of time required to remove the interior fog from the rear window:

    • Vehicle speed
    • Outside window temperature
    • Atmospheric pressure
    • Number of passengers

This system uses an instrument panel mounted switch with an integral indicator lamp that will operate for 5-10 minutes. An automatic timer shuts the lamp off automatically.

You can also shut the system off during this operation period by turning one of the following switches to the OFF position:

    • The instrument panel mounted switch
    • The ignition switch