a/c stopped workin... can someone help diagnose it?

it just stopped today when i went to a gas station it worked fine, then when i turned it back on no more a/c. im stumped and ive had about enough of this damn car breaking on me:( btw this is obsolete(martin) on my gf's account. any help would be great guys!!! thx in advance.

Unplug the PCM battery fuse or the battery for about 5 minutes.

sell it and buy a used bmw. :cool: cheaper on insurance too :D

scott :p

Is the system charge enough. If the pressure drops too low, you won't be able to start the compressor. I had this problem after my cam install. I had to use EFILive to force the compressor on to charge it. Big PITA.

how can i tell if the system is "charged enough"? i dont know to much about a/c stuff because ive never really had to deal with it on a car before... any help would be great. i dont want to take it to the dealership as its in killeen plus those guys over there are pretty much useless:(

anyone? i can hear the compressor cycle on but it only blows warm air. HELP IM GETTING REALLY SWEATY!!!

You can get a pressure gauge for checking and charging AC from most parts stores reasonable cheap. I have one if your near NW SA. I can check it.

i wont be in s.a. until later tonight:( around 10 ish unfortunately.

Where are you going to be at about 10ish?

i live in the schertz area. but i dont know if ill even have the car tonight, my gf took it to work and i may be stuck driving the other car home tonight(im at her place) i know for a fact i would be there friday and saturday however. if one of those days would be ok i would really appreciate it, driving around with a black top and black leather with no a/c in bumper to bumper traffic not getting any breaze is killer...

No problem. Drop me an e-mail and we can sort out soemthing.

If the A/C stopped blowing cold on short notice , then it's likely an electrical problem , cuz if it was a freon issue , then it would have gone out gradually. On Fords , there is a low pressure switch that could be the problem , or there is a wide open cut-out relay that stops the compressor from over speed. either one could be the problem !! The first thing to do is find an A/C shop that will do a simple A/C check to find out if the freon level is OK. If the freon level is up to specs , then you have an electrical problem !! Go to step one first , then let me know if it's electrical , and I can E-Mail you a diagram , and walk you through the proccess. But isolate the problem first , then we'll go from there !! I'm an electrical specialist , and I can help you figure it out !! ( NO Guessing !! ) Ed O'Neil

He said the compressor was kicking in. On the LS1, there isa low pressure switch that feeds the PCM and there is a table in the PCM that shut's it off at high RPM. Basically the PCM send the clutch signal from what I can tell. With EFILive, you can override the low pressure signal and turn the compressor on. I have the pressure gauge and EFILive, so we might be able to narrow this down.

LT1's use it according to throttle position. That's why I say to unplug the battery for a few minutes.

update: I shouldn't have let him take the "reliable" car. I had no idea what it was like to drive a car w/o AC. And I was driving..all day. In traffic. blech..

Thanks for all the help..whenever he has time maybe he'll try to fix it;)

I had the same problem yesterday on my LT1. The A/C Compressor wan't start. Fan blows hot air.

Filled Freon but still did not start. Electrician found out that there is good connection between the A.C switch and the PCM. Between the PCM and the A/C compressor, there is also good connection. But, some how the A/C wan't start. He tried a direct wire from the switch to the A/C compressor using a relay and it did start. Kept it like this. He thinks it could be the PCM.

Any idea or help to resolve the problem. I don't like it wired direct bypassing the PCM. Appreciate if some body could explain how the A/C is related to the PCM on the LT1 engine.

Have you tried unhooking the battery?!?!?!?

Originally posted by whitehooptie
Have you tried unhooking the battery?!?!?!?

No. But will try that if it could help. For how long should I have it disconnected to go back and connect it.

Did you check the fuse under the hood? 15A for AC/Cruise...It's easy to overlook. :D

A couple of minutes.

I get this problem every once in a while in both of my cars. Dealer wanted to charge me 500 bucks or something because they said it was the compressor.

Checked all fuses underhood and under the dash. All are okay.

The problem is that it is now running fine but bypassing every thing. Justed wired from the dash knobs to the A/C compressor direct using a seperate relay.

Originally posted by Dark Angel
He said the compressor was kicking in. On the LS1, there isa low pressure switch that feeds the PCM and there is a table in the PCM that shut's it off at high RPM. Basically the PCM send the clutch signal from what I can tell. With EFILive, you can override the low pressure signal and turn the compressor on. I have the pressure gauge and EFILive, so we might be able to narrow this down. i should have the car in s.a. this weekend, think you could help me take a look at it if you have some time? i would greatly appreciate it since the dealer is worthless and tries to double charge me on things they didnt even do work on, like my brakes a few weeks ago:mad:

Okay got the following codes:

68 A/C relay Shorted
69 A/C relay open (disapeared later)
70 A/C Clutch Relay fault
52 Engine Oil Temp Sensor Low.

Any idea how to clear these codes is appreciated.

Sounds like the A/C relay may have a problem and not switching properly, or may be corroded. I don't know where it is on an LT1. You might try and find it and see if it's working. The easiest way to clear the coded that I know of, is disconnect the battery and leave it disconnected for a little while. This should clear them.

Originally posted by obsolete
i should have the car in s.a. this weekend, think you could help me take a look at it if you have some time? i would greatly appreciate it since the dealer is worthless and tries to double charge me on things they didnt even do work on, like my brakes a few weeks ago:mad:


No problem. I'll be around. Drop me an e-mail and we will sort soemthing out.