1993 Electrinic A/C problem
Thread Starter
Intermediate
Joined: Mar 2007
Posts: 32
Likes: 0
1993 Electrinic A/C problem
I have a 93 LT1/ auto convertible that just developed an A/C problem. The A/C stopped blowing cold and the obvious problem is that the A/C compressor clutch is not engaging. The car has the electronic control system, and I've run the diagnostic trouble shooting (DTS) procedure and obtained a code 10, "UART failure"
I've talked to a couple of dealers and one independent A/C repair shop and haven't gotten a good feeling about either of their ability to properly diagnose and/or correct the problem. I'm open to any suggestions, direction, and or help.
I did check the freon level before I ran the DTS, and it was a bit low, but not low enough to trip the low pressure switch.
HELP!
I've talked to a couple of dealers and one independent A/C repair shop and haven't gotten a good feeling about either of their ability to properly diagnose and/or correct the problem. I'm open to any suggestions, direction, and or help.
I did check the freon level before I ran the DTS, and it was a bit low, but not low enough to trip the low pressure switch.
HELP!
Drifting
Joined: Sep 2005
Posts: 1,867
Likes: 3
From: Pasadena Maryland
Taken from Whatis.com :
A UART (Universal Asynchronous Receiver/Transmitter) is the microchip with programming that controls a computer's interface to its attached serial devices. Specifically, it provides the computer with the RS-232C Data Terminal Equipment (DTE) interface so that it can "talk" to and exchange data with modems and other serial devices.
Not exactly sure what this means in laymens terms? But it seems you have a computer problem?
A UART (Universal Asynchronous Receiver/Transmitter) is the microchip with programming that controls a computer's interface to its attached serial devices. Specifically, it provides the computer with the RS-232C Data Terminal Equipment (DTE) interface so that it can "talk" to and exchange data with modems and other serial devices.
Not exactly sure what this means in laymens terms? But it seems you have a computer problem?
3rd Gear
Joined: Mar 2006
Posts: 3
Likes: 0
From: Holter
Strange I just got back from the AC gay today and thought I seek the forum for any clues. I also have a 93 with the same problem. We toped up the Freon first. But the compressor is not engaging; apparently there is no 12v power to the compressor. So we cut 2 wires and got power directly from the battery. Then it started to blow cold air. Just cheeked my Hyenes manual, but I don't think the wiring diagrams in this manual covers it. I let you know if I find any clues.
Le Mans Master
Joined: Feb 1999
Posts: 9,922
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
I had my AC do this and it was a little bushing within the clutch to allow the AC clutch to engage/disingage. The Freon was fine, switches and elctronics were fine. It was a real simple fix.
Le Mans Master
Joined: Feb 1999
Posts: 9,922
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
But it did have a code. One place wanted to replace the compressor, and I politiely said HELL NO. AC compressor and GM have been around a while, and the compressor was fine, I knew it was something else, and it was the little bushing, which the other place replaces and its been working fine for years.
3rd Gear
Joined: Mar 2006
Posts: 3
Likes: 0
From: Holter
Problem solved
Hi again. My A/C is now working fine again and it wasn’t expensive at all. My A/C was a bit low on Freon but not much, but we toped it up remember? OK, apparently if the A/C has been low on Freon a code is stored somewhere and the A/C won't work until this code is cleared. The procedure for this is on page 142 and 143 in the owner’s manual. However I tried this procedure several times but it did not work out for me. Finely I just pulled the negative lead from the battery and let the car sit for 10 min, put it back on and started up. Everything is now working just fine. Hope this can solve you're problem as well!
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Melting Slicks
Joined: Jul 2006
Posts: 2,151
Likes: 0
From: Strongsville Ohio
ok guys, my AC works its just not FREEZING> i dont know if im being selfish or its just something i have to accept. i went an put some 134-a stuff in there. i was pretty full. didnt change much, maybe 2-5 degrees. its cold after a while but not freezing. is there something i can check for to make sure everything is working. keep in mind, im not SMART with car terms.
Thread Starter
Intermediate
Joined: Mar 2007
Posts: 32
Likes: 0
Not sure what you mean by "cold". First thing to check is the compressor and clutch operation. Start the car and turn A/C on. Look under the hood at the compressor (driver's side of engine) and confirm that the clutch has locked and the very front of the unit is rotating. If it's not turning you have a problem. If it's turning and the air exiting the vents inside is warm, more than 50 degrees, probably a freon/134 level problem. You need to go to a A/C shop for more specific analysis.
Melting Slicks
Joined: Jul 2006
Posts: 2,151
Likes: 0
From: Strongsville Ohio
i mean the air is cold just not as cold as other cars,,, i dont wanna be greedy buy really its not the cold.anywase bought 134-a and a pressure guage. its almost completly fulll...so i think im gunna check the engage thingy,,thanks for the directions it sure helps....
Drifting
Joined: Sep 2005
Posts: 1,867
Likes: 3
From: Pasadena Maryland
There is a SNIFFER? for lack of a better term that you use to check for leaks. The AC system in cars is sealed, no need to ever add any coolant. I do know that R-134A can be overfilled, causing the AC to blow warmer than normal. The only advice I can give you is to take it to a shop and let them evaluate the system.
Safety Car
Joined: May 2002
Posts: 4,659
Likes: 82
From: Toronto ontario
few years back when the car was stock my 93s a/c stopped blowing cold as well. The motor would vibrate every time i turned it on at about 2500 rpms. I never did fix it and after the 388 build up the first time i spun her up to 8100 the compressor caught fire on the side of the highway and smoked lol 
Thread Starter
Intermediate
Joined: Mar 2007
Posts: 32
Likes: 0
Did the green indicator above the "off" or "auto" buttons blink when the A/C stopped working? I'll try your corrective action next week. Hopefully topping off the system and reseting the computer by dis-connecting the battery will solve my problem.
Burning Brakes
Joined: Nov 2005
Posts: 1,211
Likes: 2
From: Dumas Arkansas
When my C68 was low on Freon I'd get a code 9 and the light on the control would blink for about 30 seconds when turning the car on.
http://www.idavette.net/tech/c4diag.htm
http://www.idavette.net/tech/c4diag.htm
