Aircon only works when moving!

S

Snottie

Member
Finally we have some good weather and guess what....problem with aircon! It works when we are moving but stops when we are at the lights or in traffic.

Anyone come across this before? I had the aircon serviced about a month ago where they recharged it.
 
It could be lack of airflow through the aircon rad when stationary which suggests a problem with the main cooling fan.

When the aircon is switched on the fan should run all the time regardless of engine temp. You should be able to hear the fan working by just standing at the front of the car but if in doubt, remove the bonnet and have a look. Keep your fingers out the way and be careful if you wear a tie.
Next step would be a diagnostic scan to check if any of the motorised air blending flaps are sticking or there is a problem with one of the sensors.

Cheers Spike
 
Hi i agree with spike i think you will find its the cooling fan on the back of the radiator that isnt running. This happened to vonnies tdi--it was the fan control module--large alloy cast part on the back of the radiator. It has two thick wires and two thinner if i remember correctly. We managed to get a second hand unit from ebay. I did check the fan by putting a 12v supply to the motor wires and i sprang into life.

good luck mike
 
Right there is 14v on the main 2 core plug going to the unit and nothing coming out to the fan when the aircon is active. Checking the smaller 3 core cable there is 14 v on one pin and nothing(or very low) on the other 2. So either the unit is goosed or there is no signal to drive the output. Is there a way to check the input driver signal?

Craigb, the part number is 8z0959501, is that the part you have?
 
Yep, that's the one, I bought it for £75 + P&P of £9

I never opened the packaging for the ECU as I realised I had 12V going into the fan from the ECU after ordering it and never returned it.

If you want it you can have it for £50 plus P&P as it's going to belfast

My aircon was screwy as well, constantly overheating when sat in traffic, fan wasn't running, I ordered the ECU, but it was the fan.
 
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Hold the bus!

Just rechecked and I ran the supply directly from the incoming cables to the fan and it does not run, checked the fan and there is no circuit between +&- so looks like the fan is gone.

Does anyone know how to remove the fan?

Is it a shared spare with polos etc or another a2 special?
 
There is a fan on ebay for £50 at the moment, removal of mine was easy. One screw and then a twist.

I had to disconnect the oil level pipe first which just unclips after removing the dip stick.
 
Ok, so removed the fan and got it onto the bench, took it apart and remeasured the continuity of the cables and to my surprise I started to read the motor windings again! Kept the meter attached and wiggled the cables to find that there was a break in the 0v core just after the plug. Cut and removed tha faulty pit and they you go good as new!

Thanks everyone for your help, great advice backed up with technical data and offers of parts, love it!
 
Will the fan cut in for Air con if your gas is low or does the low pressure switch stop it working ?
 
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