Okay my mom has a 92 RS. Today she told me she turned her a/c on but it only blew out hot air. What do I need to look at here? Does it just need freon? I don't really know anything about a/c systems so any help would be great.

 

Is the air actually heated air or just the same temperature as the outside air?

 

When the AC is turned on and set to the coldest setting, is the compressor kicking in and out (as it should)? It is spun buy the belt. The belt turns a clutch on the compressor. The clutch is there so the compressor only turns when it is needed even though the belt is always turning. Open the hood when you have AC on and you should easily be able to see and hear if the compressor clutch is engaging and disengaging. Is this happening?

If not, it could be one of two simple things . . .
1 - A faulty pressure switch. This is a common problem with GM (Chevy) air conditioners. They cost about $15.00 and it is really easy to replace. The pressure switch senses internal AC system pressures and sends a signal to the compressor to cycle on & off based on minimum and maximum pressure limits. It is found screwed into the top left (towards the fender well) of the receiver dryer (sometimes called an accumulator). It has two wires coming out of it.



Disconnect the wires and unscrew the old one (looks like the one in the picture). There might be a slight "psssst" of pressure released, but this is normal and there will be no loss of refridgerant. The receiver dryer contains a built in valve to prevent this. Make sure the new one has the o-ring in place and screw it in. If the o-ring is missing then you WILL have refridgerant loss. Also be sure not to overtighten. Then reconnect the wires and you should be ready to go.
2 - A bad wiring connection at the compressor. Check the wires and the connector at the top of the compressor. Sometimes they can become faulty preventing the compressor from kicking in.

If the compressor is cycling in and out when the AC is on, then you may have a low refridgerant condition. Usually there isn't a complete sudden loss of cool air. Generally the loss of refridgerant is a gradual thing and this can be noticed by the air coming out of the vents gradually beginning to be not as cool. Of coarse, if the AC hasn't been used in a long time, say over winter, then this might actually be the case. It might be time to get the system recharged.

Also, check that any fuses in the fuse panel related to the AC system ar OK.

Hope some of this is helpful. Good luck.

 

Hey thanks for all the info That will help me out a lot. I will examine the car later today and report back with my findings

 

Ok I finally had a chance to check this out. I did not hear the compressor engaging and disengaging. It should be pretty noticeable right? So I figured I would just get a new pressure switch since it was only $11 bucks. Got that and put the new one on but still no change. I checked the wiring at the compressor. It looked fine, I unplugged them then reconnected them but still no change.

When I got the pressure switch there were 2 different choices. One switch for R-12 and one for R-134A. I got the R-12 one because the compressor has a sticker saying it takes R-12 I think that is the refrigerant this car has. Could it be possible the car has 134 and I need the other switch? Or could the compressor be shot?

 

i bet you it's not a pressure switch and it's out of freon, and r12 is expensive as hell, you need to put gauges on it to see if there is freon, then leak test it and convert to 134a or pay up the butt for r12

 

R134a conversion is much better in the long run if there are plans on keeping the car.

But Also...

I have heard of some various 'replacements' for R12. A quick google search gave me this right off the bat -- http://www.freeze12.com/

And here's another too -- http://www.refrigerantsales.com/autofrost.html

A guy I used to know that did many conversions recommended this, but also - be sure to really read the manual good. It doesn't seem to be an issue with this - but in some cases, draining of ALL of the old Freon is a MUST.

 

The progress has been slow but I finally got a guage to check the refrigerant level. Well the guage didn't move at all when I put it on so I guess its out of freon.

Looks like I will try Freeze 12 out then.

 

Freeze 12 isn't going to cool enough for Florida's hot humid weather. You should go for Autofrost instead. Look for my thread on converting to Autofrost. I'm getting low 30's duct temps.