dtorres

I recently added Freon to the ac and it worked fine. The next day I wasn't gettting cold air. 2 days later I checked the freeon pressure and it is still holding the same amount of Freon I put in the beggining. So there is no leak. When I was adding the freon the compressor would turn on and do its thing. Now when I turn on my ac it doesn't do anything. I think the compressor turns on whenever I am adding freon. Help anyone?

1989IROC-Z5.7L

iTrader: (2)

Sounds like a bad low pressure switch.

dtorres

Thanks for replying so fast.
Where is the low pressure switch located and how do I replace it?
Another thing that dawned on me is where I am adding the freon. The chrome cylinder looking part (i think it's called the dryer) has a connector coming out of it. Is that where i am suppose to add the freon to?

dtorres

I have a 91 rs 305 tbi. And I think it's an R12 or whatever comes stock on that year.

1989IROC-Z5.7L

iTrader: (2)

The left arrow is the low pressure switch. The right arrow is where you charge the ac. Do not suggest mixing r12 and 134a!

dtorres

A picture is worth a thousand words!! Thanks, I will replace the switch and give it a try.

Guro 305

All you have to do to test it is to get yourself a paperclip, fold it in half, remove the plug from the low-pressure switch on the bottle and pop the paperclip into the plug (one end in one hole and one end in the other.

It'll force the compressor to kick on and stay on. Wait about two minutes and go feel if your A/C is blowing cold now. At that point, pull the paperclip out and goto Autozone or Advance Auto and buy a new low-pressure switch. It just unscrews/screws on. No big one.

quickkris2006

iTrader: (2)

what do u have to do to change from r12 to 134a?

87bucketgta

Before you replace the switch, clean the contacts first mine wasnt workling or kinda hit and miss like yours, cleaned the contacts works great now!

Guro 305

Two options: 1) Take a screwdriver to the lowside port (you didn't hear that from me) to get the freon out and buy yourself a complete retrofit kit for R134a.

They sell a few different kinds but you don't want to cheap out and buy the best one that would offer some new rings, three cans of freon, a can of oil, a hose, etc.

2)Screw R134a and buy yourself a can of A/C leak detector and run it while checking the lines for about ten to fifteen minutes with a U/V light either in your garage or at night so the leak detector would really glow. If you are low on freon to begin with, you may need to jump the lowside switch to keep the compressor running to do this. If you have leaks depending on how bad they are, use some stop leak for tiny (and I mean tiny) leaks or just replace whatever parts are bad. Then buy yourself three cans of Freeze12 which is a R12 substitute which doesn't require retrofitting the system.

dtorres

I tried the paperclip test and nothing happens. I checked for power with the tester and there is no power coming out from both sides. I did all this with the ignition on, then with the engine turned on and ac on full blast. I also checked the ac/heater fuse under the dash and it's all fine. Help.

Guro 305

Check the lowside plug with a volt meter or light tester. No need to check the switch itself since there is no power coming from there to begin with.

Try stripping a small section of the wires and put your volt meter there to see if it's the actual plug or if the actual lines themselves are not putting out power. Sounds almost like you are getting no juice to the lowside pressure switch. You may have damage somewhere to that cable or the plug or both.

dtorres

I checked the insides where the paperclip went and there is no juice.
Tomorrow I will check the wires and see if there's any juice there.
There is some kind of relay below the low pressure switch. I checked it and it has juice.
I know this might sound crazy but, can I bypass a power wire straight to the compressor or the switch?

dtorres

Thanks Guro 305 and everyone else for helping me out.
Okay, There is power in the plug, I never had a good ground on my tester. So I did the paperclip trick and the compressor stood on. I am still getting hot air after 5 minutes of waiting. I do know I need a low pressure switch now. I also made a huge mistake. I added r134a to an R12 system.oooops. That might've damaged the low pressure switch. Could that mistake mess up the whole ac?? I bought an ac hose cleaner to clean and flush out the old freon. I found out you can order r12 freon. That's the only thing I can come up with to get my ac going.

Guro 305

I don't believe it'll mess anything up because remember the only difference between R134a and R12 is basically the ports. The entire system is exactly the same. Some people have even used I think it's called R434 which is freon for home systems on them without the conversion and it's worked. R134 is less dense (I think I'm right) than R12 so that's why it'll leak out of an unretrofitted R12 system.

You can buy Freeze12 right on Ebay and not have to retrofit anything but you should check to see if your system has a leak first. Check on Ebay, they sell complete Freeze12 kits with hoses, oil, check-leak, stop-leak, etc. Or, you can goto your local Autozone or Advance Auto and buy the retrofit kit for R134a as well. I can tell you this that R134a, seems to lose it's efficiency in a retrofitted system at idle ie. it'll not blow as cold until you start moving forward again. R12 didn't have that problem and from what I've read, neither does Freeze12. Good luck and whatever you do, don't cheap out on it.