Aircon pressure switch

It simply unscrews but can be VERY tight if it's never been taken off before,luckily the fitment is self sealing so you won't get a face full of green liquid.

When you say it doesn't work,do you mean it all switches on and there's no cold air,or the pump clutch doesn't even pull in?

Call me stupid is it the pipe that unscrews from the black part?
Aircon has been tested, full up, pressure tested, no leaks
Tried 4 climatronic units, compressor clicks into action ok, fans all work as they should, all wiring under battery examined just in case, all fuses ok, in fuse box and ontop of battery I've tried everything
Had no Aircon for two years now! So any suggestions much appreciated pal

I can't remember as it was about 5 or 6 years ago I had to do this,but as with most people who've had the same problem it turned out to be something else.In my case it had leak which needed fixing before it was regassed.

Are you seeing the correct external temperature figure in the instrument cluster and climate control display?

its got like a metal hex bit you need to unscrew from the smaller pipe entering it (did it today) and only takes 10 minutes, if you just search mk4 golf pressure switch the aircon one should come up, pretty sure they're all the same? and around £20 get a OEM quality one and not some £5 knock off

oh and try and grab the smaller pipe with some grips as its only soft and mine started to bend where it was so tight without them.

If you mean the external temp, yes it seems to be pretty accurate, the same figures displayed in the climatronic and the instrument binnacle. Nothing comes up when it was hooked up to laptop
Do you think one of the temp sensors might be up the swanny?

Thanks Big Bang I will be careful with that pipe!
Imagewerx, do you think it might be the pressure switch if everything else appears to be working ok? I also did the climatronic self testing diagnostic process and all 4 units so far have been ok. I took one unit apart and cleaned everything and put it back together all excited.... Nothing

If the clutch kicks in that says the pressure switch is working as i was under the opinion that it directly controlled the compressor clutch to turn it on and off regulating pressure?

As well as that high/low pressure switch,there are also an ambient temperature and and thermo cut-off switch that all need to be working for the rest of the air-con system to be working properly.Sorry I can't tell you where they are,but the temp. switch has a black/white wire going in and a green/blue coming out and the thermo switch green/blue in and green out.Bypass these with any short length of wire and let us know what happens.

But.................the pump working (or at least spinning externally) could indicate an internal fault with the pump?

Ooo blimey. Right ok, I'll look at the wiring diagram and have a look around. just wanted to eliminate everything first before I remove the compressor
So there is the temp sensor in the climatronic unit, the sensor on top of the dash, the external temp sensor and the one you've described (ambient) which I've got to find and a thermo cut off switch ?
I hope it's one of these and not the compressor
Thanks chaps help is much appreciated

I've just removed the aircon from my A3 so if you want any parts to try let me know.

Sootpig, cheers pal
Does your pressure switch look like my one? Has yours got any part numbers on it?

Imagewerx, I'm not ruling out the compressor....

Vernv5 said:

Imagewerx, I'm not ruling out the compressor....

Click to expand...

I don't think there's any way to test it without taking it off the car and giving it to an aircon repair workshop.

Meaning the car is out of action? It's off to the garage Tuesday anyway, broken coil spring