Skoda Octavia Elegance 2005

I’m having air-conditioning problems. The car has the Climatronic E87 control.

First, the AC fan started to work intermittently some weeks ago. The internal fan would start and stop erratically and randomly start or stop on braking or cornering. After a couple of weeks of this, it then started working normally but then the air conditioning would not blow cold.

I took the car to a local AC specialist who connected his pressure gauges to the AC system. He said that;

1) there was plenty of refrigerant in the system but that the compressor wasn’t compressing;

and 2) the VAG AC compressors have no magnetic clutch, but have a riveted internal connection which is intended to shear if the system has a fault. The verdict was that a new compressor was needed (£500 ish).

However, the internal fan has now started misbehaving as previously. I took it out, expecting problems with the brushes, but it all seems in good condition. The fan speed control is an electronic device (solid state relay?) with an aluminium heat sink, it is not a series resistor. The fan itself works (if you connect 12V directly to it, by-passing the electronic device). There is a 12V input power input to the electronic relay device (2 thick wires) and there are also 2 thinner wires which I would have expected to be a 0-12 V control signal. The fan itself is £200 ish, but I’m not certain that it is the fan that is faulty. Does anyone know what the output control voltage from the Climatronic controller should be?

Does anyone recognise these symptoms, are there any such known problems with the Climatronic AC system?

Can anyone recommend a good AC specialist in NE London, West Essex area.

Sorry if this has been asked, I can't get the search to work. It gives me about 800 irrelevant posts for every search.

Edited 27 July, 201015 yr by Onetap

I have never seen one of these controllers, but I imagine the heatsink is for a power transistor (which contols the fan speed). The power transistor may have gone bad or you may have a bad connection/dry joint. A competent electronics technician should be able to identify and replace the transistor and reflow the njoints.

Do your have any fault codes? Does your outside temp display in the car still work? I only have AC and not climatronic control but I had been having similar sounding problems with the fans turning themselves on and off at random and the compressor not engaging. I eventually found that a wire going to the outside temperature sensor had broken under the battery. Once it was fixed the temp display retuned and the fans stopped acting up and the AC now works.

Thanks for the replies. The electronic speed controller contains several power transistors, a PCB and other electronic components. There are no obviously defective joints, but it's beyond my limited knowledge.

The AC specialist said there were no fault codes, but I don't know what equipment he had and whether it would show up any of the AC control systems codes. The outside sensor is giving a sensible temperature on the dashboard display so I'd assume that is working correctly.

I think the fan randomly going on/off on braking or cornering suggests a loose connection, so my plan now is to take the Climatronic controller out, check the connectors and check th continuity of the two control wires going to the fan's speed controller. If that doesn't show up any faults, I will reassemble it all and take it to a Skoda dealer to get them to conect it to their system and tell me what's wrong with it.

The AC man said the fan failure wouldn't cause the compressor to fail, which leaves me unconvinced that the compressor is defective; it is not likely that the compressor and fan would simultaneously develop unconnected faults.

Any other suggestions are welcome.