Heated Glass Element: Description and Operation

IHKA E38 REAR WINDOW DEFROSTER







On the E38, rear window defroster operating strategy depends upon whether ambient temperature is above or below 5°F (-15°C)

- If ambient temperature is below 5°F (-15°C), pressing the rear window defroster button (ignition switch in "Run"), causes the control/panel module to turn on the defroster for 17 minutes, and then switch it off.
- It ambient temperature is above 5°F (-15°C), the control/panel module runs the defroster for only 10 minutes before switching it off.

Reactivating the defroster by pressing the button again causes the defroster to run for an additional 5 minutes, regardless of ambient temperature.

If the ignition is switched "Off," the defroster is shuts off, but the timer keeps operating. If the ignition is then switched "On" again with time remaining, the defroster automatically turns "On" again until the timer runs out.

If battery voltage drops below 12.2 volts, the defroster automatically switches "Off."

Unlike IHKA E32 systems, the rear window defroster is not automatically activated when maximum defrosting is requested.

* Ambient temperature is supplied to the control panel/module over the K-Bus.

E38 WINDSHIELD BASE/WASHER SPRAY JET HEATERS







E38 vehicles are equipped with a windshield base/washer spray jet heater system similar to the one found on 1988 and 1989 E32 vehicles On E38 vehicles, however, both heater systems are powered at the same time by the same relay:

- The lower portion of the windshield contains electrical resistance heating elements (similar to those on a heated rear window) which, when powered, prevent the wiper blades from freezing to the glass.
- The washer spray jet heaters are located on the underside of the hood and are designed to prevent ice from forming on and obstructing the washer nozzles.

The control panel/module monitors the signal from the ambient temperature sensor (K-Bus) and automatically activates the windshield base/washer spray jet heater relay when:

- Ambient temperature is lower than 38°F (3°C), and
- The ignition is "on" and
- Battery voltage is greater than 12.2 volts.

When ambient temperature exceeds 43°F (6°C), the windshield base/washer spray jet heaters are switched off.