GF88.79-P-2000CE Heat Left/Right Outside Rearview Mirrors Function

GF88.79-P-2000CE Heat Left/right Outside Rearview Mirrors Function
- as of model year 09


Function requirements, general
^ C. 61 ON or c. 15 ON (only with rear window heater)
^ On-board electrical system consumer shutoff not active
^ Particular (local) front power window not active

The status of circuit 15 is made available on the interior CAN (CAN B) by the electronic ignition lock control unit (N73).

Heat left/right outside mirror, general
The mirror heater is switched on automatically depending on the outside temperature and dew point temperature (with code (581) Comfort automatic air conditioning).
If the heated rear window is active, the mirror heater is always active as well.

Heat left/right outside mirror, function sequence
The mirror heater is operated depending on the dew point temperature and outside temperature.
The outside temperature is recorded by the outside temperature sensor (B14) and transmitted by the front SAM control unit with fuse and relay module (N10/1). The instrument cluster (A1) transmits the value to the front SAM control unit via the interior CAN. The instrument cluster calculates the outdoor temperature value on the basis of the vehicle speed and engine temperature and sends this value to the interior CAN.

The dew point temperature is determined by the dew point sensor (B11/12) (with code (581) Comfort automatic air conditioning) and relayed via the climate control LIN (LIN-B8) to the automatic air conditioning control and operating unit (N22/7) and sent via the interior CAN.

The left front door control unit (N69/1) receives these values and switches the mirror heater (M21/1r1) in the left outside mirror (M21/1) on or off. The i front door control unit (N69/2) receives these values and switches the mirror heater (M21/2r1) in the i outside mirror (M21/2) on or off.

The mirror heater is switched on while the engine is running (circuit 61) if:
- Outside temperature ≤ Dew point temperature + 2 °C (programmable via IS tester)
- outside temperature < 15 °C

When c. 15 is on, the mirror heater is switched on when the rear window heater is switched on.

The mirror heater is switched off while the engine is running (circuit 61) if:
- outside temperature ≥ Dew point temperature + 5 °C (programmable via IS tester)
- Outside temperature > 18 °C=

With c. 15 the mirror heater is switched off if the rear window heater is switched off.

If the outside temperature value received is not plausible, the mirror heater is always switched on. An integrated temperature protection switch protects the outside mirror against overheating.

If the dew point value is not plausible, a default value applies. If no dew point is available, the substitute value of T = 13 °C is used.