Got an EBII Fairmont with the automatic climate control. 2 days ago the air conditioning died. There's been a hissing noise coming from the dash on the passenger side for some time (if I remember correct) and it's still there (even though the air con is not functioning properly). If I turn the A/C off on the climate control (i.e. so just the fan is running) the noise goies away - so it is directly related to the air con running.
Any ideas?
When I say not running I mean the climate control says AC is on, but the air isn't cold. AFAIK the air con has not been regassed in the past 10 years.

well no gass could be a drama

also the aircon compressor clutch may not be engaging

have similar problem with my EB. the a/c bloke says it is more than likely the unit (evaporater/condemsor???) under the dash. I have had mine regassed and checked for leaks. The a/c guy could not find any leaks on the rest of the system but it lost its cold again within a month or so. he said the dash will have to come out to replace the faulty bit at around $600 all up

Run a self test, to make sure there are no errors, depending on the error the A/C won't engage.
If that's okay, set and run to maximum cool, then run monitor mode - the evaporator temp should be down in single figures. Make sure you can hear the compressor cutting in and out. If the evap temp doesn't change much, then it's most likely low refridgerant.

The above is all in the doco.

Sounds like you also have a vaccy leak - probably the junction connector behinfd the glovebox has come loose.

A quick check for gas level is to have the car running, aircon switched on and look in the sight glass on top of the receiver/dryer. Occasional bubbles mean low gas, no bubbles mean good gas OR no gas.
Check the latter by unscrewing the test cover nearby which will reveal a valve, push this in gently with a probe [do not have your face in the way]. If the system has gas it will jet out with a loud hiss and chill your fingers. Replace cap.
If there is no chilling or hissing you have no gas and a leaky system.
As Snap says, there's a doco about replacing all major aircon components and 'o' rings, my Holy Book ATM. Much professional 'leak finding', as per 'pop058', unfortunately often means checking only what they can see, which costs a bit if the leak is under the dash, as you will lose the gas again.
So best to check if you actually have enough refrigerant in the system FIRST, if you haven't the clutch won't engage anyhow.
Paul

Thanks, I'll go through the doco - http://www.fordmods.com/forums/documents.php?doc=9