Heat left/right outside rearview mirrors function - GF88.79-P-2000CE

WARNING: This page is about a different car, the 2011 Mercedes-Benz C350, 2010 Mercedes-Benz C350, 2009 Mercedes-Benz C350, and 2008 Mercedes-Benz C350. However, it is still accessible from the selected car via links, so may be relevant.

MODEL 204.0/2 as of model year 2009

/YoM 08

MODEL 204.3

MODEL 204.9

Function requirements, general

Circuit 61 ON or signal "PT_Rdy" (drivetrain already) set or circuit 15 ON (only with heated rear window function ON)
On-board electrical system consumer shutoff not active
Particular (local) front power window not active

The electronic ignition switch control unit (N73) transmits the circuit status c. 15 via the interior CAN (CAN B).

Circuit status 61 or the "PT_Rdy" signal is sent by the CDI control unit (N3/9) (with diesel engine) or the ME-SFI [ME] control unit (N3/10) (with gasoline engine) via the chassis CAN (CAN E)

Heat left/right outside mirror, general

The mirror heater is switched on automatically depending on the outside temperature and on vehicles up to 31.5.10 with code (581 Comfort automatic air conditioning and depending on the dew point temperature.

On vehicles as of 1.6.10, the mirror heater is switched on only depending on the outside temperature.

If the heated rear window function is switched on, the mirror heater is switched on as well.

Heat left/right outside mirror, function sequence

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) (up to 31.5.10 (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 front door control unit (N69/2) receives these values and switches the mirror heater (M21/2r1) in the outside mirror (M21/2) on or off.

If circuit 61 or signal "PT_Rdy" (drivetrain ready for operation) is set, the mirror heater is switched on, when

the outside temperature ≤ dew point temperature + 2 °C (programmable over diagnosis tester)
Outside temperature < 15 °C

When circuit 15 is ON, the mirror heater is switched on, when the heated rear window function is switched on.

If circuit 61 or signal "PT_Rdy" (drivetrain ready for operation) is set, the mirror heater is switched of when

the outside temperature ≤ dew point temperature + 5 °C (programmable over diagnosis tester)
Outside temperature & gt; 18 °C=

When circuit 15 is switched ON, the mirror heater is switched off, if the heated rear window function 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 Tdew = 13 °C is used.

	Electrical function diagram for mirror heater	PE88.79-P-2055-97FAB
	Overview of system components for electric mirror	GF88.79-P-9996CE