Residual Engine Heat Utilization Function

GF83.75-P-2000T Residual Engine Heat Utilization Function

Function
Residual engine heat utilization enables the vehicle to be heated even when the ignition is OFF. For this purpose the system utilizes the engine residual heat blowing it through the blower into the passenger compartment. The residual engine heat utilization system can only be used when the ignition is switched OFF. The stationary heater (only vehicles with code (228) stationary heater) has priority.

Operating principle:
When the REST button is pressed on the AAC control and operating module (N22) or comfort automatic air conditioning (N22/7), the following program run is given:
- Blower: Fixed at 25 %; immediately after switching on; no manual steps possible; Display is masked out.
- Flaps: controlled or manual, as with ignition ON
- Fresh/recirculated air flap: fresh air position; button and LED locked.
- Activated charcoal filter flap: No activated charcoal filter operation possible; button and LED locked.
- Coolant circulation pump (M13): controlled
- Heat exchanger shutoff motor (M16/32): controlled

Special conditions:
- IN REST the set function keys are displayed, as before ignition OFF.
- IN REST rear window heating mode is not possible.
- IN REST, DEFROST mode not possible.
- If the position "0" was selected with circuit 15 ON, the position before "0" is set in REST. (Save)
- Stationary heater has priority over REST mode.

End of program:
- Press the REST button again
- End of maximum time of 30 minutes (restarting possible).
- Battery voltage less than 11.5 V: text REST/ function diode flashes on and off.
- Battery voltage less than 11.3 V: text REST / function diode flashes on and off for 5 seconds, then the utilization of residual engine heat shuts off. - Ignition ON.
- Ignition ON.