Rear Window Defroster

IHKR1 REAR WINDOW DEFROSTER







When the rear window defroster button is pressed, the control module energizes the rear defroster relay to heat the rear window.

- The defroster operates at full power (100% on) for 10 minutes to clear the rear window; this is the "fast melt" period.
- The control module then switches to timed relay operation (40 seconds on/80 seconds off) until the engine is shut off.
- If the engine is restarted less than 3 minutes after shut off, the control module resumes intermittent operation.
- If the rear window defroster button is pressed during timed relay operation, the control module starts another 10 minute "fast melt" period.
- If the defroster button is pressed during "fast melt" operation, the control module shuts off the system.
- On early production 1989 vehicles, the defroster will operate with the ignition "On," and the engine "Off." On later production vehicles, however, the defroster relay coil must receive battery voltage from the KI. 61 relay for the defroster to operate.