91 A/C problems
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Joined: Jul 2012
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91 A/C problems
Just purchased a 91 and the prior owner said the a/c didn't work, noo problem. I did a conversion to R134, had to get power to the a/c clutch to get the freon in but managed to get in three cans and system was blowing cold. Plugged compressor back into power source and NOTHING, clutch would not engage. Soo, I read the owners manual and it say's to reset a/c pull the interior light and radio fuses for 1 min. , reinstall and unit should work. IT DID, until the next time I get in the car and the climate control is flashing again and NO a/c. I've done this 3 times already, TIRED of resetting my radio. Do any of you guys know what is causing this problem ?
Safety Car
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From: Fredonia WI
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I assume you have the C68 (electronic) controls. If the HVAC display is flashing, there's an error code set. Did you pull the code and see what it is?
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Disconnected the battery, + and -. Pump tries to kick on for about a min. then it engages for about 3mins. and kicks off. When I shut off the engine and restart the light flashes on the HVAC again.
About reading the code, do you mean with a code reader hooked into the port under the dash or from the HVAC screen ?
About reading the code, do you mean with a code reader hooked into the port under the dash or from the HVAC screen ?
Melting Slicks
Joined: May 1999
Posts: 2,230
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From: Allentown, Pa
Disconnected the battery, + and -. Pump tries to kick on for about a min. then it engages for about 3mins. and kicks off. When I shut off the engine and restart the light flashes on the HVAC again.
About reading the code, do you mean with a code reader hooked into the port under the dash or from the HVAC screen ?
About reading the code, do you mean with a code reader hooked into the port under the dash or from the HVAC screen ?
Safety Car
Joined: Mar 2005
Posts: 4,448
Likes: 1,216
From: Fredonia WI
2025 Corvette of the Year Finalist - Unmodified
2024 C7 of the Year Winner - Unmodified
2023 C4 of the Year Finalist- Modified
2020 C4 of the Year Finalist - Modified
2019 C4 of Year Finalist (performance mods)
2018 C4 of Year Finalist
You don't need a code scanner to read the HVAC codes (most standard ones only show ECM codes anyway)
To display fault codes from the HVAC system, press and hold both [fan up] and [fan down] buttons simultaneously for 5 seconds. Pressing the [fan auto] button after that will display any HVAC fault codes (eg, I had code 09 – low Freon)
If you have code 09 like I did, after you add "freon," you may have to clear the code from the HVAC before the compressor will come on again. On mine, the compressor would not turn on after adding R134a (my system was converted). I think this is a safety feature to keep the compressor from burning up. I reset my code 09 (low freon) by disconnecting the battery for 30 seconds. Once there are no codes in the HVAC, if the system has enough freon the compressor should come on. If not, there's a problem somewhere else.
To display fault codes from the HVAC system, press and hold both [fan up] and [fan down] buttons simultaneously for 5 seconds. Pressing the [fan auto] button after that will display any HVAC fault codes (eg, I had code 09 – low Freon)
If you have code 09 like I did, after you add "freon," you may have to clear the code from the HVAC before the compressor will come on again. On mine, the compressor would not turn on after adding R134a (my system was converted). I think this is a safety feature to keep the compressor from burning up. I reset my code 09 (low freon) by disconnecting the battery for 30 seconds. Once there are no codes in the HVAC, if the system has enough freon the compressor should come on. If not, there's a problem somewhere else.
Melting Slicks
Joined: May 1999
Posts: 2,230
Likes: 4
From: Allentown, Pa
ghlkal is right about the pulling the codes..they most likely will not show up. I must be getting old and forgetting things
Use this link to see what the HVAC shows.
https://www.corvetteforum.com/techti...=193&TopicID=2
Let us know how it goes
Use this link to see what the HVAC shows.
https://www.corvetteforum.com/techti...=193&TopicID=2
Let us know how it goes
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Thread Starter
Navigator
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Just did the HVAC code read. Pressed the arrow up and down together, got a display of, -00, pressed the fan icon and a 09 appeared. Did I do it correctly ? If so, you were right on the low freon. The conversion kit I used (IdQ) came with 3 cans of freon and I used all 3 ! Was that not enough ? I'll pick up another can tomorrow and try adding more and do the battery disconnect thing. This is really frustrating.
Le Mans Master
Joined: Dec 2000
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From: San Diego, Ca
Sounds like the wrong procedure (charge) to me. You can't mix gasses which includes air and 36 ozs is more than it needs for a conversion. If it's cycling enough to trip the fail safe with that much gas, the orifice is probably plugged up with junk. You need to empty it, flush it, replace the Accumulator. Add appropriate and compatible oil. Pull a vacuum and recharge. More gas will probably trip the high limit or if that's broken, blow a hole in something - so don't do it.
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SunCr was right. Added more freon and set off the saftey valve. The system was supposedly drained and vacumed of the R12, then recharged with 3 cans of IdQ freon w/oil. When I do the reset as stated in the owners manual and the clutch finally engages all is good, until I shut the car off and restart it. Then the light starts to blink and the HVAC code reads "low freon". I've had it, gonna take it to the A/C shop and have them figure it out. Thanks Guy's for your help !
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Sounds seriously plugged up and if a Shop did this, they need to fix it! Particularly if they didn't replace the Accumulator in the first place and it's now fallen apart and ruined a bunch of stuff. If you're in CA, Law requires a detailed invoice of all the parts, High and Low Side Reading, Center Vent and Ambient Temp. Report crappy work to the BAR (Bureau of Automotive Repair).