air conditioner

Hi, I'm new to this site...

I'm having problems with my air conditioner...It will work for awhile, but then it will cut out and just blows warm air. I will shut it off, along with the fan, the a minute later turn them both on..and the air will be working for a while...then cut out again. I own a 1995 GMC Sierra 1500.
If anyone can help, I'd appreciate it much.

Thats a tough one.... are you driving when it blows warm or are you parked?

Hi,

Thanks for your reply...yes, it's when I'm driving is when it kicks out....I'm thinking that it is the plug where it connects to the cylinder.

Cat44

Hi, I'm new to this site...

I'm having problems with my air conditioner...It will work for awhile, but then it will cut out and just blows warm air. I will shut it off, along with the fan, the a minute later turn them both on..and the air will be working for a while...then cut out again. I own a 1995 GMC Sierra 1500.
If anyone can help, I'd appreciate it much.


I have a 95 GMC Sierra and my air conditioner was blowing warm air, but all I did was recharge the freon. It works fine now.

Sounds like your low pressure switch on the accumalator. You get get this at a local parts store for about $12. Replace the oil ring when you do this. If it blows cold then then just starts blowing warm, this should be it. A way to check this is: with the ac blowing warm air, disconnect the wire at the low pressure switch. Install a wire jumper across the two terminals. The compressor should kick in and the accumalator will suddenly get cold. If it does this, take the jumper out and change your switch.

GOOD CALL DEEPEE!
I have 3 certs in auto a/c and I missed that one. That is definatly the first place to start seeing as how it blows cold, then warm, then cold again. I was actually suspecting a slight clog in the orifice or accumulator, but I have a bad habit of over analizing things and overlooking the easy obvious stuff.

I agree with Stacynb.

The low pressure switches on those model will cause some intermittant problems..when the AC is turned on and not blowing cold, check to see if the compressor is engaged...if not, tap on the LP switch..if the compressor engages then the switch is your problem

I see alot of folks are viewing this post. If you suspect a faulty low-pressure switch, than by-passing the switch will not test the switch unless you know your system pressure readings. If you by-pass the switch the compressor clutch will engage regardless of the condition of the switch. Follow GMMerlin's advice to test the switch if pressure readings are not available. P.S. I still think Cat44 is just a little low on refrigerant, but then I've been wrong before.

Well...... the same thing happened to mine last summer, doing the same as CAT44's. It would blow cold then warm, then later on, cold again. I went through the instructions in my previous post. Replaced the switch and never had a problem since then.

Gooseneck: If you were low on freon, how could it blow cold air, then warm, then cold again? Seems like if you were low on freon, it couldn't blow cold at all?

CAT44: What did you find out?

Hi DEEPEE, I'm not saying that it's not the switch, it very well could be. My hunch is just based on the fact that leaks are much more common than intermittent switch failures. Just a guess thats all. One thing I would bet money on though, CAT44's problem is one or the other so either way he should benifit from this discussion.

Without the benefit of a set of A/C gauges to determine if there is any refridgerant in the system and years of experiance with these trucks, failure of the low pressure switch is more common than leaks on this system.
That being said, a truck that is 10 years old may have leaked enough over time not to engage the switch but with what the original poster stated about the air blowing cold then blowing hot, I would say this is a electrical problem (switch)and not a pressure problem (leak)

An "Intermittent" switch (bad contacts in switch sometimes completing the circuit and sometimes not) and a borderline pressure in system sometimes throwing switch and sometimes not, would produce the same symptoms. Thats why I say it could be either-or. But I still stand by my hunch that Stacynb is right. Although I actually hope it is the switch, it will be a easy fix for Cat44 if it is.

Hi, I also have a problem with my air conditioner. It always blows cold air but the fan fluctuates by as much as 50%. The fluctuation is always in the negative range.

Same prob. on my 97. Cold then warm. If I screw
around with controls, I can get it going cold again
for a little while. I will check this switch before I
look into recharging. I don't know exactly where
this part is but I can probably research and find out.
Thanks alot to all replies.

[QUOTE=MyTOY]Same prob. on my 97. Cold then warm. If I screw
around with controls, I can get it going cold again
for a little while. I will check this switch before I
look into recharging. I don't know exactly where
this part is but I can probably research and find out.
Thanks alot to all replies.[/QUOTE


I think the plug (the one that plugs into the condenser is loose) actually it could be the wires. I haven't had nothing done with it, been way to busy this summer. Thanks to everyone for their inputs, I don't feel alone known that others have the same problem. Cat44

Just found this site today and what a wealth of information. I have a 2003 Sierra and had the exact same issue. It was the low pressure switch. At the time my truck was still under service with GM so they did the work and replaced it. I had tried adding freon before taking it to GM but it did not correct the problem....Good Luck!

[I have a 2003 sierra 1500 x cab. I have had the same problem. My ac will switch over to heat in the summer time then rite when i need it for the bitter cold new england winter my heat shuts off and blows cold air. I think my truck is possessed! Not happy with my GMC! Any help with this would be great!