Heat left/right outside rearview mirrors function

Function requirements, general

 Circuit 61 ON

 No overvoltage or undervoltage

 On-board electrical system consumer shutoff not active

 Particular (local) front power window not active

Heat left/right outside mirror, general

The heated outside mirror is automatically switched on and off dependent on the outside temperature and the dew point temperature.

 If the rear window heater is switched on, the mirror heater is activated in parallel. See separate function description "Rear window heater (HHS)".

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Heat left/right outside mirror, function sequence

The outside temperature is measured by the outside temperature display temperature sensor (B14) and is read in by the driver-side rear SAM control unit with fuse and relay module (N10/1).

The driver SAM control unit transmits the outside temperature via interior CAN.

On vehicles with code (581) Comfort automatic air conditioning, the dew point temperature is determined by the C-AAC control and operating unit (N22/7) by evaluating the information from the C-AAC multifunction sensor (B31) and is transmitted to the interior CAN.

On vehicles without code (581) Comfort automatic air conditioning, a substitute value is used for the dew point temperature.

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The left door control unit (N69/1) and right door control unit (N69/2) receive the temperature values and switch the mirror heater (M21/1r1 and M21/2r1) on or off.

Switch-on requirements:

- Outside temperature  Dew point temperature + 2 °C
(programmable via STAR DIAGNOSIS)

- outside temperature < 15 °C

Cut-off conditions

- Outside temperature  Dew point temperature + 5 °C
(programmable via STAR DIAGNOSIS)

- 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.

If the dew point value is not plausible, a substitute value applies.

If no dew point is available, the substitute value of T = 13 °C is used.