GM Service Manual Online
For 1990-2009 cars only

The rear window defogger system consists of a tinted glass that has a number of horizontal element lines and 2 vertical bus bars. The element lines consist of a compound of ceramic and silver. A portion of the glass forming operation bakes the element lines and the bus bars into the inside surface. The feed wire connects to the bus bar on the left side. The ground connects to the bus bar on the right side. The system operates on battery voltage. Under some conditions, you cannot detect heat from the window. The necessary amount of time for removing interior fog from the rear window varies. The conditions that affect the amount of time may include the following conditions:

    • The vehicle speed
    • The temperature of the outside window
    • The atmospheric pressure
    • The number of passengers

This systems uses a switch on the console. The switch has an integral indicator lamp. The system operates for a period of 5-10 minutes. An automatic timer turns off the system. The switch or turning off the ignition also turns off the system.