luke4907

iTrader: (5)

There's no A/C board on here so I guess this is the best place for this: My A/C works sometimes, other times, it doesn't. What I've been able to figure out is that when the car is cold, I can turn the key to ON and turn A/C on and off and I'll hear a click when I turn it on (sounds like the clutch grabbing or maybe a really loud relay). When I run the car, the A/C runs, and it usually will quit on me sometime on my drive. When I stop the car and turn it off, then back ON, switching the A/C back and forth doesn't make the clicking noise again. It does work sometimes, and I don't have to recharge the system to get it to work. It sounds like a relay or some bad wiring to me. Maybe the system is too high/low with refrigerant? Is there a relay that needs to be replaced? Does anyone have an idea why my A/C just quits on me?

Vader

The "click" you are hearing is likely the A/C compressor clutch operating.

This is very typical operation for a system that is low on refrigerant, or if the A/C is operated at relatively low ambient temperatures. There is a low pressure cutout switch on the accumulator. If the low side refrigerant pressure drops below 25 PSIG, the A/C compressor will cycle off. It won't cycle on again until the low side pressure rises to at least 45 PSIG. This is to prevent inadvertent freezing of the evaporator and damage to the compressor from low oil/refrigerant charge.



You can verify this by installing a jumper wire in the connector for the pressure switch. If the compressor remains on, the switch is probably cycling and doing its job. Do not leave the wire in for more than a test run, since you may damage the system without a functioning pressure control.

Connect a refrigeration guage manifold to the low side test port and you will likely see the pressure drop as described. Have the system tested for leaks, and replace lost refrigerant and oil as required.

luke4907

iTrader: (5)

just wanted to say thanks, Vader. finally got around to resolving this (heat is unbearable). low pressure cutout switch is not functioning. I connected the two wires together and the a/c kicks in. pressure appears to level out just above 45, which makes it so that the air isn't very cold. This is probably due to my underdrive pulleys, right? Would replacing the compressor be worthwhile to negate this? is this switch replaceable without having to depressurize the system? thanks for all your help.

Trickster

That switch is replaceable without depressurizing the system although you might lose some of the pressure when you do it.

luke4907

iTrader: (5)

so what you're saying is just have the new one in one hand (ready to replace the old one) and pull the old one off with the other?

Vader

What Trickster is saying is that you will lose charge when you replace the low pressure cutout. The system should be evacuated before changing the switch.

Snuffit

you wont really loose charge when you pull the low pressure switch off...there is a valve in there to keep it from all leaking out...you might hear a slight depressurization (sp?) but thats just the area from the valve to the switch escaping

Trickster

That is correct and is what I meant in my post. The low pressure switch just screws onto the connection on the accummulator.

luke4907

iTrader: (5)

oh sweet... In that case, I can put off replacing everything (which was a thought if I was going to have to depressurize the entire system). BTW, does anyone make a better-than-stock replacement compressor and etc? When I break down and replace everything, I want my A/C to make me feel like I'm in a freezer. Again, thanks for the help

Trickster

There are several compressors that are on the market right now. You would just have to search for them. If you go to any of the auto parts stores they will have either remanufactured compressors or a new one that they can get for you. If you decide to get a new unit for your car, be aware of this little fact that they may or may not tell you. There is a warranty with these compressors (1 year if it is remanufactured or 2 year if it is new) however, this warranty only applies if you replaced the related items with new ones at the same time. The related items would be the receiver/drier (accummulator) and orifice tube or expansion valve. At advance auto, you do not have to buy all the parts from them to get the warranty. You just have to show proof that you bought the parts and installed them.