Fan Control Function

Fan Control Function

mbGF07.61-P-3023G-001
Shown on Engine 111
A1 Instrument cluster
A9 AC compressor
B11/4 Coolant temperature sensor
L5 Crankshaft position sensor
M4/3 Electric suction fan engine/ A/C
N3/10 ME-SFI control unit
N19 AC control and operating unit
N22 Automatic air conditioning (KLA) control and operating unit
N76 Engine/AC electric suction fan control unit (further designation N65/2)
CAN Data bus

The ME-SFI control unit indirectly actuates the fan through the engine/AC electric suction fan control unit.
The fan specified speed is transmitted by the ME control unit to the engine/AC electric suction fan control unit by means of a pulse width modulated signal. The on/off ratio is 10 to 90%, in which the following means e.g.:
10% electric suction fan OFF
20% electric suction fan ON, minimum speed
90% electric suction fan ON, maximum speed

Note: If the actuation is faulty, the electric suction fan rotates with maximum rotational speed.

The status of the air conditioning or automatic air conditioning is transmitted from the instrument cluster via the CAN to the ME control unit. The fan specified speed is dependent on this status.

Note: CAN capable instrument cluster required, that the HHT or STAR DIAGNOSIS is programmed according to with/without air conditioning or automatic air conditioning.

Engine 112 at production start-up as of 3/97 with viscous fan clutch, fan control phased in as of 7/97.

On engine 137 and in Model 203, 209, 211, 230 an electric suction fan is built-in with integrated control. The engine/air conditioning electric suction fan control unit is deleted.