Rear Window Defroster

IHKA E32 REAR WINDOW DEFROSTER







The IHKA E32 rear window defroster is a two-stage defroster. Pressing the defroster button causes the defroster to operate at full power (100% on) for ten minutes. The control module then switches to pulsed operation (40 seconds on/80 seconds off).

On vehicles equipped with control modules having software version "01" or "02", the defroster will continue to operate in 40 on/80 off mode until the engine is shut off (or the defroster is switched-off manually). If the engine is restarted within three minutes, the IHKA control module resumes defroster intermittent operation.

Beginning with software version "03" (from 12/88), the rear window defroster turns off automatically after 20 minutes of pulsed operation (similar to IHKR/F3).

For all software versions, pressing the rear window defroster button while the system is operating in fast-melt mode shuts off the defroster. And, if the button is pressed during pulsed operation, the system switches to fast-melt mode for another ten minute period.


NOTE: On early-production E32 1988 MY vehicles, the engine does not have to be running for the rear window defroster to operate. On later-production vehicles, the rear window defroster is only powered when the engine is running.


The rear window defroster turns on automatically whenever "maximum defrost" mode is selected. If "maximum defrost" is then turned off, the rear window defroster continues to operate for its normal cycle.