W210 Fan/Aircon/Heating probelm

[Keith2]

The heater/aircon fan sometimes takes a long time to come on. Sometimes it starts after about 30 secs other times it can take up to 15 mins. The longest time it's taken to start is about 45 mins.Sometimes it starts for a few seconds and then stops.

Once it starts it's usually OK and keeps going, heat and aircon work OK. Doesn't seem related to inside or outside temp. Bumping the temp wheels to cold or hot doesn't make any difference either, neither does hitting the recirculation button. Makes no difference whether the EC button is in or out.

Does anyone have any ideas or is this usual?





its a W210 '99 E300TD 66k

 

[dieselman]

Interesting that you have another electrical fault. Check all the connections to the relay and fuse boxes.

The fan could have sticky brushes, try banging the fan itself when it wont work, it's under the glovebox. Alternatively the switch could be faulty or the fan relay could be burned out / sticking.

 

[piestore]

heater blower inop

Hi

The fan motor is controled by a regulator bolted onto the bottom of the fan assembly this should have a three pin plug going to it One thick red wire ( +12 volts ) one thick brown wire (earth - ) and one thin wire can't rember the colour (Possible black and green) . Test you have a good 12V between red and brown if thats ok check signal wire this should vary between 3 and 8 volts as the fan speed control is turned, if this is ok check the out put from regulator ( thick red wire and thick blue wire to fan motor) this should also vary in voltage as the fan speed is controled, if this is Ok blower motor is faulty

It is quite common for the regulator to be faulty, This would be identified by inputs being OK and no output to fan motor

Note, tests can only identify the fault when the fan is not running !!!!!!!
What I mean is the fault must be present at the time of the test.

 

[Keith2]

Thanks to you all. It's a greate help even knowing where the fan is. As suggested checked the fan controller and it was faulty. Got a replacement from Dronsfields by return of post and all is OK.

Thanks again.