Air conditiong issue

[2008camrydriver]

Hi all. I live in quite a humid area so need the air con running on cold mornings to keep the window de-fogged, however the last few mornings the air con hasn't turned on as normal. The fan is on and when I push the 'AC' button the light comes on and stays no (no flashing) but theres no change in engine rpm or the tell-tale hissing of the evaporator working, and the windows stay fogged. The stange thing is that once the engine has warmed up a bit it works fine!!!

I don't know if it's to do with the winter cold as it's worked fine before even when the car has been completely iced (which was only the other week!).

I just want to know if someone else has had a similar issue or if anyones gotr any ideas before I start diagnosing.

Quick stats:

'94 V6 GL (NZ)

374,000Km

Manual air con system.

[2008camrydriver]

Did a bit of diagnosing today and found the following:

- When on maximum cooling the AC compressor works, the engine idles up like normal and the cooling fan speeds up to maximum. Looked at the sight glass and it is clear when running and foams up then clears when turned off. There is also a temp difference between the compressor inlet and outlet pipes.

However the system is still working intermitantly, and the other day wasn't working when I got to work.

I'm begining to think it's an electrical problem...just not sure exactly where. If it is it will most likley be a wiring issue or a faulty sensor issue, possibly the low pressure switch.

Has any one had a similar issue? If so what was the outcome?

To reiterate:

When the system works it works great and like it always has since I got the car.

When it dosen't the following happens when the fan is on and the AC button is pushed:

The ac button lights up and stays lit. There is no sound of the ac compressor clutch engaging or the evaporator working and no engine idle up.

[Sanctuary]

Seeing how your car has that many Ks on it, the problem could very easily be a mechanical one. Im no expert on ACs but it could be that the comressor is giving way or that the clutch is worn out which would explain it working sometimes and others not. For it to be a problem with a sensor you gotta start noticing a patter, otherwise im not sure how a sensor or a wiring fault could cause this (again i could be completely wrong). Ill look into compressors for you and give you a proper answer once i get a chance