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2002-2005 Range Rover MkIII / L322
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Discussion Starter #1
I recharged the AC at a shop today and it blows ice cold. But I don't have a engine fan shroud around the engine fan which could be a concern. There's this mystery connector that my mechanic said there is a small box. What is it?


I was driving the car with the AC on and at the stoplight I saw the temperature needs moved slight pass center. When I started moving again it quickly got back to dead center. I only experienced this in another car when one of my aux fan was seized in the summer.

I think the AUX fan is not running as per ATC ECU request.

Engine Cooling Fan Control
The engine's electric cooling fan is controlled by the ECM. When the compressor is engaged the ATC ECU sends a
fan speed message between 0 (off) and 15 (maximum speed) to the ECM, via the K bus, instrument pack and CAN
bus. The ATC ECU requests the cooling fan on when:
l The vehicle speed is less than 44 mph (70 km/h)
l There is no fault with the compressor clutch circuit
l Battery voltage is less than 16 V
The fan speed requested depends on the pressure in the refrigerant system. The higher the pressure the faster the
fan speed that is requested. When vehicle speed increases to more than 50 mph (80 km/h) the ATC ECU changes
the fan speed request to 0 until vehicle speed decreases to less than 44 mph (70 km/h) again.
If battery voltage increases to more than 16 V for 5 seconds the ATC ECU changes the fan speed to 0 until the voltage
decreases to less than 15.8 V.
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