this an 03 impreza wagon.
I've checked the A/C relay and fuse and they're good.
The green switch light comes on and the engine alters tone when the switch is pushed in.
The compressor wheel isn't spinning when A/C switched on. There is some small resistance to hand turn but it isn't stuck or seized.
I tried having the system re-gassed at one of these drive in places but was told it hadn't worked and to get it seen at a garage for system faults.
Is it likely the compressor has packed up? It hasn't been used that much.
Any ideas?
thanks
Trev

 

There is a low gas protection switch by the headlight that stops the compressor running if insufficient gas pressure. You can bridge this with a paper clip to determine whether the compressor works. If it does, then you have a gas leak and will need to most likely get the O rings replaced and a re-gas.

* if it couldn't be regassed, surely that means there is a leak?

 

thanks for the help.
I assumed from the re-gas that it had been successful in that regard but there was another fault. The drive-in were only up for re-gas and no more.
I'll check the compressor, I'm looking for a pipe behind the nearside headlight, or probably offside now that I think about it?
thanks
Trev

 

yes thanks, the compressor is working, I bridged the switch behind nearside headlight. There is gas pressure at the high pressure port but guess it's not enough and the leak occurs when the system is brought up to the required pressure.
Trev

 

I had a similar issue with my Bug. The aircon was working (compressor etc) but wasn't very cold. I had it regassed at Kwik Fit and they commented that the gas pressure was very low but managed to refill it. Ice cold air for a week and then compressor suddenly stopped. I figure that the low pressure was being contained by the O-rings but once it was regassed, the increased pressure was too much for them and they failed.

Take it to a specialist and providing it's just the O-rings (and not a leak in pipework or rad) then it shouldn't be too expensive and will last the life of the car.

It's worth noting also that when systems are regassed, they also include a lubricant to stop the O-rings drying out. So it's worth getting the system drained and regassed annually.

 

thanks again for the help.
I have it booked in next week to get it sorted.
I've learned a bit about the system of which I didn't have a clue before.
thanks
Trev

 

 

update on this.
Had the car checked for leaks and re-gassed, all good but garage report still not working and that the relay isn't getting enough power. i.e. if they bypass the relay and give the compressor 12v all works. They think something is interfering with the supply to relay and have advised me to seek services of auto electrician.
I've bridged the low pressure switch as before and it all works, lots of cold air. Is it likely the switch is faulty and are they easily replaced.
thanks
Trev

 

The pressure switch is a dual switch working both high and low pressure. AFAIK it's only available as part of the liguid line pipework.


Below are the two relevant sections of the workshop manual
HVAC system pdf

HVAC diagnostics pdf

 

thanks for that Don, the diagram is really helpful as I might see where, if any, interference might be coming. It's likely of my own doing as I've got so much stuff going on in the engine bay
thanks again
Trev