Thermostatic fan

my thermostaic fan kicks in early and wont go off till long after i turn ignition off,doesn’t run hot but sits on half way.can i adjust the fan startup.Rory

Hi Rory,

You haven’t given us much information about your car or where you are located but I have checked and both V6 and V8 petrol engines seem the same in this this area. Also there don’t seem to be any differences between NA and ROW.

The cooling fan has its own control module which takes inputs from the Powertrain Control Module and the Air Conditioning Control Module. The PCM has inputs from the engine coolant sensor among other things and the input from the ACCM will depend on demands from the aircon. There does not appear to be any easy adjustment for the cut-in temperature and actually I’d be surprised if there was one. Maybe there are differences for different markets but if you can change it (doubtful) the means of doing so are likely only accessible through the IDS system.

To start tracking the problem down will involve discovering whether the Fan Module itself is faulty but I would start by trying to determine if it is responding to an input from the PCM or the ACCM. The Electrical guide does not give the location for the FCM so I would expect to find it as part of the fan assembly. It has a seven pin connector. The input from the PCM is on pin 5 (brown/yellow wire) and on Pin 7 (white/black wire).

Two final things. If your car happens to be an early 4.0 litre V8, the water pump is a known issue as the impellors disintegrate. Also, the temperature gauges are somewhat over-reassuring and can sit at the normal position for rather too long so it might be worth checking what the real coolant temperature is. The fan may be doing its job correctly.

Eric
Church Stretton, UK