Heat left/right outside mirrors, function

P88.79-2147-09

1 Outside temperature

2 Terminal status

3 Switch on mirror heater

4 Circuit 61 (engine running)

B14 Outside temperature display temperature sensor

N69/1 Left front door control unit

N69/2 Right front door control unit

N73 EIS [EZS] control unit

CAN-B Controller area network bus, class B (interior compartment) (CAN B)

G2 Alternator

M21/1r1 Mirror heater

M21/2r1 Mirror heater

N10/1 Front SAM control unit with fuse and relay module

Function requirements

 Circuit 61 ON (engine running)

 No overvoltage or undervoltage

 Power window not operated

Function

The mirror heater (M21/1r1) in the left electrically adjustable and heated outside mirror and the mirror heater (M21/2r1) in the right electrically adjustable and heated outside mirror consists of one heat resistor each, located on the foil on the rear of the mirror glass.

The left front door control module (N69/1) and right front door control module (N69/2) act as the power supply and control regulated switch-on and switch-off of the heating resistors.The left front door control module (N69/1) and right front door control module (N69/2) receive for this purpose a CAN-B (CAN-B) message from the front SAM control module with fuse and relay module (N10/1).

At an outdoor temperature of < 15 °C the mirror heater (M21/1r1) and the mirror heater (M21/2r1) is switched on and at an outdoor temperature of > 19 °C switched off.If the temperature value received via CAN-B (CAN-B) is not plausible, the mirror heater (M21/1r1) and the mirror heater (M21/2r1) are switched on