Autobahn

I recently replaced the two buttons (air recirculation & defroster) on the right side of the CCU .

Now the front oil cooler fan on the driver side starts running as soon as I turn on the ignition.

Any idea what is causing this?

Metal Guru

Some good info here: http://p-car.com/diy/fan/. I found it to be helpful.
Sounds like you might have messed up your $CCU$ but lots of troubleshooting is now in your future.

turboholic

On a LHD car, the front cooler on the driver side is for your aircondition, not for the oil, if the fan there is running that usually means that your AC is switched on.

To make identification easier:

Standing in front of the car ---> left handside = oil cooler
---> right handside = AC cooler

If AC cooler fan is running constantly maybe you messed up something when you replaced the two switches for defrost and recirculation??

Autobahn

OK, it makes sense that the CCU would cause the AC cooler and not the oil cooler to turn on.

Now I have to find out what went wrong...

Cheers.

Boeing 717

Where did you get those switches (buttons)???

Autobahn

I bought a non working 993 CCU on ebay since it was cheaper than to order new switches/buttons.

Metal Guru

It controls both

Autobahn

I am relieved to report that the running fan was due to operator error.

The AC button was pressed, i.e. switched on and this apparently causes the AC fan to run even though the fan speed on the CCU is switched to 0.

It is all good now...

turboholic

dunavantent

In the summer time i unplug my oil cooler temp switch. That way the fan stays on all the time. My car runs nice and cooool.