Troubleshoot Air Conditioning

[99capergrandam]

I haven't driven my GA in several weeks and today I noticed that it's not working. All it blows is air from the outside....not cool at all. How can i tell if it just needs to be charged or if it's a problem with the compressor?

[rixGAphx]

The compressor has an electric clutch within the pulley assembly.
The compressor won't spin and compress the refrigerant if the clutch isn't working.

1. Check the compressor fuse.
2. Check the battery.
If the battery is weak or failing, or if the alternator is failing, or if the battery cables are dirty/corroded/loose, then there isn't enough electrical power to operate the clutch (this is often accompanied by the 'ABS' light coming 'on' and the auto tranny feeling like it's slipping).
This could also result from a car just setting for three weeks while the battery slowly drains.
3. Even though the switch turns on the blower, there might be something wrong in the switch that is failing to turn on the AC compressor. I don't think this is a likely possibility, since this isn't a common GA problem.
4. The clutch itself can fail; this is common with many cars, including GA's.
The pulley ALWAYS turns (whether AC is on or not). When the clutch engages, the 'backside' of the pulley also turns. If the clutch isn't working (whether for lack of electricity or because it has failed), the 'backside' of the pulley doesn't turn.
Therefore, if the 'backside' of the pulley engages/disengages, the problem is NOT the clutch.
5. Refrigerant *usually* leaks out slowly, so the cooling ability gradually gets poorer.
It's rare for it to all leak at once (unless somebody messed with a hose or connection and caused a massive all-at-once leak).
For you to be getting no 'coolth', the compressor would have to be nearly empty.

Once you check out the electrical items above, it would prolly be best for you to go to a good mechanic for an 'AC Service'.
Though there are 'Refrigerant fill kits' available for ~$15US, and even a clutch replacement is DIY, there are other possibilities (bad expansion valve, for example) that can cause your symptoms and they aren't easy to figure out or e-analyze.

Good luck.
-Rick

[99capergrandam]

Thanks rixGAphx for the reply. Here's what I do know: normally when I push the AC button, shortly there after you could here the engine slow down slightly and the rad fans would come on. Now when i push the AC button, nothing happens. Does anyone know how I can check to see if power is being sent to the compressor when the AC button is pushed? Also, how many fuses/relays are there and where are they normally located? Thanks again!

[Quantum]

A quick check to see if you have any freon at all in the system, is to find the "Low" side port of your AC, usually indicated with a blue plastic cap, and depress the needle in under that cap with a screw driver just for a second. It should hiss very loudly. If it does, you have freon. If it doesn't, you now longer have freon in the system. Even if it hisses, you may not have enough freon in the system. Most systems need between 25-45PSI to operate.

You can buy a cheap gauge at Wal-Mart for like $25US that comes with a can of R-134a freon with a sealant in it. Might be a cheap fix.

Regards,

[99capergrandam]

OK I tried what Quantum has recommended and there appears to be no pressure at all. Is this something that decreases over time or is this a sign that I have a leak. I don't want to get it recharged if it's only going to leak out again.

[pokesmot]

thats what sucks about AC systems.


if you have a leak you have to pay to have it recharged just to find the leak. then it has to be emptied, fixed, and recharged again.

the reason your compressor wont cycle is because there is a pressure switch that prevents the clutch form engaging the compressor in the event that the AC pressure is either too low (from a leak) or too high (overcharging) this protects the compressor from damage.


if you wanna fix it it will cost you a couple hundred dollars probably, to get it charged leak tested, emptied, fixed, then refilled again.

[99capergrandam]

To bad they couldn't just fill it with compressed air to check if there are any leaks.