Ac Problem..won't Work In Warm Weather!

[nhawan]

This is a strange one...the Climate control on my galaxy tdi ghia mk2 (2003) won't work when it's warm weather over 18 degreesC.

In cold weather it works fine and you can tell by checking the AC pipes in the engine bay. one gets really cold and the other gets hot. The compressor engages fine and can be seen spinning.

 

The problem is when the weather is hot the compressor fails to engage. You can see it constantly trying to engage and then release every 2-4 seconds and the engine revs drop intermittently when this happens. This affects the cars drive due to the constant on-off load from the clutch engagement. :P

 

I checked with vag-com and there is an AC pressure switch (intermittent) code.

I am thinking its due to pressure being higher when the weather gets hot. Could this be the problem or is it looking like its a switch problem?

 

I've searched the forums but no one seems to have a problem exactly like mine.... :blink:

[seatkid]

AC pressure switch is a 3 way device i.e. lo/normal/hi. So it looks like yours is a high pressure problem due to too much gas (has it been regassed recently?) or a faulty switch or possibly a dicky connector/wiring.

[ghr]

Have flashing display and vagcom fault A/C Pressure Switch intermittent. Is the switch under the bonnet? Is it replaceable? Although the a/c display flashes it does blow coldish (very 'ish) air when on 'Auto'. If there is a leak surely all the refrigerant would have evaporated by now? Last ones to tough it were Frauds.

[chrispb123456]

Have flashing display and vagcom fault A/C Pressure Switch intermittent. Is the switch under the bonnet? Is it replaceable? Although the a/c display flashes it does blow coldish (very 'ish) air when on 'Auto'. If there is a leak surely all the refrigerant would have evaporated by now? Last ones to tough it were Frauds.

Hi there

The switch is replaceable without degassing, it's located behind the area of the o/s fog lamp about

[mikej]

Hi chrispb123456 how is the pressure switch changeable without degassing, how does it monitor the pressure ? does it simply plugin then ?

[chrispb123456]

Hi chrispb123456 how is the pressure switch changeable without degassing, how does it monitor the pressure ? does it simply plugin then ?

There is a valve fitted in the pipe where the switch screws in.

The switch will disable the system if the pressures to low or to high to prevent damage to compressor.

[ghr]

Have flashing display and vagcom fault A/C Pressure Switch intermittent. Is the switch under the bonnet? Is it replaceable? Although the a/c display flashes it does blow coldish (very 'ish) air when on 'Auto'. If there is a leak surely all the refrigerant would have evaporated by now? Last ones to tough it were Frauds.

Hi there

The switch is replaceable without degassing, it's located behind the area of the o/s fog lamp about

[chrispb123456]

Certainly not, they are only OK for a straight forward regas (providing they put the correct amount of gas and oil in) a specialist is guy who has a good working knowledge of auto aircon systems on a variety of vehicles and is able to diagnose a fault without the guess work.