Originally Posted by
Rollinz
No point in changing or testing the low/high pressure switch just yet.
Do you know how long the car has ran without a/c not working?
Has the filter dryer ever been changed?
If i was to look at it this is what i would do in order..
Recover gas left in system,
Fill with nitrogen and check for leaks (even tho it sounds like you dont have any)
Then change the dryer filter and vac down for a minimum of an hour,
Refill with refrigerant and check system... Once at this stage if its still not working i would the Go on to check wiring faults and pressure switches
Biggest failure i find to do with a/c is no one ever seems to change the dryer filter! This shoud be done at least every 2 years to keep the system from sludging
generally good advice, but he's already had it emptied, leak tested and refilled as stated at the beginning of the post, and it didn't work, although the compressor clutch does when powered directly. this already indicates a problem with the controlling circuit.
by the way, what would the system sludge up with? an r134a system with PAG oil unless messed around with in some way will remain clean internally for many years and that is based on seeing warranty returns from a wide variety of vehicles over the years.
the most likely problem that you might have with an old filter drier that has not been dried well enough by vacuum is moisture in the system that can freeze at the expansion valve and block the flow causing a high pressure cutout.
i just checked autodata and unfortunately that model does not have any self diagnosis features unlike later models, so it will be a case of using the wiring diagrams to find out what's wrong, or replacing components.
my advice would depend upon your capabilities. as already mentioned, you need to be careful with this stuff as you have already found out that running the compressor without the electrical safety circuits in place can lead to high pressures and refrigerant discharge which is unlikely to be toxic (as it should be R134a), but environmentally damaging (1300 times worse than CO2
) and can seriously harm you through cold burns, loss of eyes etc.
for the sake of the cost of a pressure switch, which in my opinion is the most likely culprit (assuming you've checked all fuses), i would change that, but that first involves emptying the system (professionally recovering the refrigerant, not just venting it out). as i said previously, you will have lost some oil when the HPRV blew off, so it would be worth having that topped up with the correct oil before vaccing it out for at least an hour as previously advised and then recharging and retesting by someone who knows what they are looking at on the pressure gauges which can tell you a lot about the system.
hth
EDIT: unless you have climate control, not manual, in which case fault codes are outputted but i can't copy and paste from autodata
but 00792 is pressure switch and if you can read any others i can translate them for you