My A/C stopped working WHILE DRIVING.....HELP!!!

Hello All,

I have a 2001 Camaro SS, 6-Spd, 93,000 miles, and I am the original owner. I was driving the car yesterday with the A/C running fine and cold. All of a sudden, the air started coming out warm. I pulled over and noticed the A/C Compressor Clutch was no longer spinning. I have never had a problem with the A/C prior to this. I immediately checked for a blown fuse. Under the hood in the foreword most of the 2 fuse bays, I saw on the lid over the fuses: "A/C COMP". This seems like an A/C Compressor Relay rather than a fuse. You can't tell if it is blown. It is a little gray plastic box with 4 prongs on the bottom. I went to a auto parts store and bought a new one. The guy there told me he sells about 20 a day, and it is most likely my problem. Well, I put the new one in, and it DID NOT FIX THE PROBLEM. I did pull it out and try it turned 180 degrees as well. As a side note, the drive belt is fine, the Freon level is fine, and I was able to reach in the engine compartment and spin the A/C clutch by hand easily, so it doesn't seem to be seized.

Any help with other things to check out/try would be GREATLY APPRECIATED. Thanks.
Tom

I just assisted my shop foreman with a replacement on a TrailBlazer. He told me the magnets inside the compressor fail, causing the compressor shutdown. The pulley will still spin, but the compressor is completely useless. How many miles on your car?

I put that "93,000" in the first sentence of my post. Thought it was important.

Whoops!! Still a little sleepy. :lol:

There weren't any loose connections at the compressor, right?

No problem. That is one thing I did not check. Do I need to get it up on the car ramps to check that out? Where is the connection?

I saw an electrical plug near the front of the compressor, and it is plugged in tight.

Ok. Sounds like a compressor failure to me.

agree

Thanks all. I just need to verify if there is power going to the plug, that plugs into the compressor. One thing I am slim on is electrical diagnostics, and I don't have a proper tool to check it.

A simple $5 test light will tell you if you have power to the compressor. I'm thinking you probably do and the compressor died (as others mentioned) but I'd put a test light on there to be sure. Then you'll know what you need to do.

Thanks FBJ,,,I will look into that.

I have unplugged the 2 prong plug that clips to the compressor, and plugged it back in to make sure it was tight. I am very light on electrical testing skills. Is there any way you can walk me through how to do the test in laymen's terms? I do not have a test light yet, but I assume it has 2 leads (one positive and one negative?). I'm very good at doing things I have never done before.

The compressor electrical connection plug, once unplugged, has 2 electrical connector holes in the end. Starting at this point, can you tell me exactly how to perform the test? I could make an educated guess, but would really appreciate it. Thank you.....!

If I were to make a educated guess, do I put the positive lead of the "Test Light" into EITHER of the two holes in the end of the plug and the negative lead to the engine block, or is one hole, possibly the negative one, the wrong hole to put the positive lead into? Thanks to all those who chimed in, especially on a Sunday afternoon. I AM great with Mechanical work, but as I said, I am a little weak on Electrical diagnosis. Thanks All, and bless you.

Should be a 2 wire plug, one ground and one power. Usually the color will give it away. Black ground and power for AC is usually green.

Either way it's real simple. Unplug it, ground the (clipped) end of the test light to anything that looks like a solid ground. Turn key on and turn on the AC. Take the sharp end of the test light and touch inside the plug (either wire doesn't matter, but one of them should light up the test light). If it doesn't light then rest assured power isn't there.

I'd probably test power at the low pressure switch too, make sure it's at least getting that far.

As a side note, jump the battery with the test light just to make sure the light is working ;)

Thanks AGAIN FBJ, It is a 2 wire plug, and I did notice a Black and Green wire. Your instructions make complete sense to me. I assume the car should NOT be running during this test?

What I don't understand is what the "Low Pressure Switch" is, and where it is located. I assume the testing procedure is the same. Thanks so much for your help,!

Correct, engine doesn't need to be running, just key on and AC on should produce power to the compressor.

The pressure switch is under the hood on the passenger side, right next to the passenger strut tower. Can't miss it. I believe it's attached to the ac line rather than the dryer/accumulator.

It will also have a plug, power runs through this switch before going to compressor so if there isn't any power at the compressor then this switch is the next place I'd look to make sure it's plugged in, secure, and no wires chaffed.

Thanks again FBJ. I will look for it. I understand this switch will keep power from going to the Compressor, therefore keeping it from running if the Refrigerant level is too low.

It is just so perplexing that I had ICE COLD A/C one minute, then warm air the next minute. The guy at the parts counter was sure my A/C Compressor Relay "Popped,,as he put it". He said he has been selling 20 a day recently. I am wondering if I got a bad Relay from the Auto parts store. It was not a GM part, and it was MADE IN CHINA...!!!....YUK,!

Hey FBJ, I found the Low Pressure Switch very easily like you said, which is attached right to an A/C line by the Passenger Side Strut Tower. It is a 3-Pronged plug with 3 wires (Purple, Green, and Red with a Black Stripe). I assume I test this like the Compressor plug,,,just keep trying (Probably the Red Wire) until the test light, lights up (Or not).

I still have to run out and get a test light.

Question, If I did get a bad A/C Compressor Relay, will either of these 2 connections get power? I read on the net about a guy using a paper clip to jump the connections where the relay plugs in, just to see if that makes the Compressor Clutch kick in. That would indicate a bad relay? He also said to be very careful too. With 4 plugs in the relay plug, I wouldn't know where to put the paper clip anyway. BAD IDEA? Thoughts? I am also trying to determine if I got a bad relay from the store.

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Originally Posted by NastySS

Hey FBJ, I found the Low Pressure Switch very easily like you said, which is attached right to an A/C line by the Passenger Side Strut Tower. It is a 3-Pronged plug with 3 wires (Purple, Green, and Red with a Black Stripe). I assume I test this like the Compressor plug,,,just keep trying (Probably the Red Wire) until the test light, lights up (Or not).

I still have to run out and get a test light.

Question, If I did get a bad A/C Compressor Relay, will either of these 2 connections get power? I read on the net about a guy using a paper clip to jump the connections where the relay plugs in, just to see if that makes the Compressor Clutch kick in. That would indicate a bad relay? He also said to be very careful too. With 4 plugs in the relay plug, I wouldn't know where to put the paper clip anyway. BAD IDEA? Thoughts? I am also trying to determine if I got a bad relay from the store.

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Yes you can jump the pressure switch plug with a paper clip. If there is at least power to that pressure switch plug, jumping that would then send power to the compressor.

Not sure if either would have power at all if you have a bad relay though. Don't have schematic in front of me, but I tend to think all power has to go through the relay before either of those plugs.

Well FBJ,,,,,,ARE YOU READY FOR THIS????? I JUST GOT IN MY CAR TO GO TO THE AUTO PARTS STORE TO BUY A TEST LIGHT. After 3 days with no working A/C, I decided to give it a try. The A/C KICKED RIGHT ON,,,,!!!! Right away I pulled over to check the refrigerant level via the fill port (I had a Refrigerant level gauge with me), just in case it was low, and was possibly causing the issue. The needle on the gauge pointed 3/4 of the way into the "Blue "Filled" Section of the Gauge" (The range of the Blue section is 25-45 PSI), so approximately 40 PSI.

Also, I had the GM A/C Relay back in, not the replacement one made in China I had bought this past Friday. Now I am thinking of the possibility of a problem with the Rotary Dial that turns on the A/C. Let this simmer in your brain for a while. After simmering, any thoughts would be appreciated. Man,,,this is Whacky Monday!!!!

The only thing I did today, was to unplug then plug back in, the Low Pressure Switch 3 prong electrical plug. I can tell you that it was plugged in securely, and there was nothing unusual like dirt, grease, grime, or a loose connection.

I have been in and out of the car about 6-8 times today and every time so far the A/C has turned on,,,no problem. I guess I will just wait and see if this situation happens again. For now, I am going to do nothing, no diagnostics for electrical current at specific points like I was planning earlier. OH, and you lied about the 5 dollar Test Light. It was $5.99!!!!....lol

How high was your RPMs when the A/C quit working. When you get over a certian RPM the a/c cuts out. But it should come right back when the RPMs come down.

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Originally Posted by blackcar

How high was your RPMs when the A/C quit working. When you get over a certian RPM the a/c cuts out. But it should come right back when the RPMs come down.

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^^I had this in the back of my mind as well. Could be another possibility. :yup:

Sorry guys, I didn't get any notifications that there was a response to this thread. This is why I did not answer until now.

Thanks for the suggestion, but I was just driving normally. I know from having the car 11 years, that when you really "Get On It", the A/C will cut off temporarily. If I feel the need to "Get On It" for any reason, I always turn off the A/C before slamming the gas pedal (If the A/C is on of course).

Right now, the only thing that makes any sense, is a "Possible" intermittent issue with the A/C control knob??

This is really a Head Scratcher, isn't it?

Sounds to me like your system is low on refrigerant. Low pressure drops when rpms go up, so when you hammered it and the rpms climbed, your pressure was low enough to break continuity (open) on the low pressure switch - which kills the voltage to the compressor. At least that's my theory. You can test that by slowly reving it up in the driveway with the air on and see if the compressor's clutch kicks out.

Thanks 79FB, but if you read all my updates, you will see that I checked my Refrigerant after my A/C Compressor started to work again, and the levels are perfect (40 PSI) and nowhere near low. You said "When you hammered it". I am not sure where you got that from, but I didn't "hammer it" anytime during this issue. Thanks anyway for trying to help.

What is your low side pressure at 2,000 RPM?