Residual engine heat utilization function

N83.10-2156-09

The function requirement is "tml. 15 OFF" (ignition off). The residual engine heat utilization makes it possible to heat the vehicle for a period of 30 min. The residual engine heat utilization system (REST) uses the residual heat of the engine for this purpose.

Activation

The REST is activated via the air conditioning system, heater booster, residual heat rotary switch. Activation of REST is shown by illumination of the LED next to "REST". After activation, the climate control control and operating unit regulates the following components depending on the position of the temperature selector switch:

– Circulation pump (M51)

– Front blower motor (M4)

The circulation pump ensures circulation in the coolant circuit.

The recirculated air solenoid valve (Y95) regulates the air flow which flows via the heater heat exchanger. The front blower motor delivers the warmed air from the air conditioner housing via the air outlets into the vehicle interior depending on the position of the air recirculation mode and air distribution rotary switch.

 The front blower motor always operates at stage 1 even if another setting was set via the blower knurled wheel switch.

 If the temperature selector switch is set to "MAX cooling" (the temperature selector switch is turned all the way to the bottom into the detent position), the temperature is regulated to approx. 18 °C.

Deactivation

The REST is deactivated if of one of the following states applies:

– The air conditioning system, heater booster, residual heat rotary switch is turned to another position.

- The status "terminal 15 ON" (ignition on) is activated.

- The operating time of 30 min has elapsed.

- The battery voltage drops below 11.5 V.