Taz211

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 ?

ghlkal

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?

GreyGhost

You need to clear the codes for the compressor to kick back in. Disconnect the negative battery cable for a few minutes and then try it again.

Taz211

No I havent checked the code yet, a friend of mine has a code reader and I'll have him plug it in and see what he comes up with. I'll try the battery disconnect and let you know what happens.

Taz211

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 ?

GreyGhost

Then there is another problem, you cleared the codes and something is triggering a code. It could be low on freon. You will need an OBD1 scanner to read the codes or you can do the old paper clip trick and see what see what code it is throwing. Just use the port under the steering wheel to pull the codes.

ghlkal

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.

GreyGhost

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

Taz211

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.

SunCr

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.

Taz211

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 !

SunCr

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).