1993 c4 HVAC Issue
Thread Starter
1st Gear
Joined: May 2020
Posts: 1
Likes: 0
1993 c4 HVAC Issue
Good evening all , hope your staying safe.
i have a 93’ corvette that is having an issue with the hvac system.
when I purchased the car the a/c was not working. I pressurized and found a leak. I converted the system to R134, and made the repair. Once this was fixed I went and powered the climate control system up and found the digital control was not powered ( this issue was happening before repairing the a/c, but repaired a/c leak first before addressing current issue) I cycled the key and then the unit powered up and I had full control, but even tho the a/c came on and I was able to command full fan speed, it was coming out very minimally as if the blend door was stuck midway. (This issue with the fan speed doesn’t matter whether it’s a/c or heat being commanded)
some times when I turn the car on , the climate control is not powered , sometimes works fully but has the issue I stated above , and sometimes the display shows “- - “ and it feels as tho heat is commanded by default.
Just wanted to see if you guys had any issues similar to this or any insight on where to begin looking
thanks and stay safe !
i have a 93’ corvette that is having an issue with the hvac system.
when I purchased the car the a/c was not working. I pressurized and found a leak. I converted the system to R134, and made the repair. Once this was fixed I went and powered the climate control system up and found the digital control was not powered ( this issue was happening before repairing the a/c, but repaired a/c leak first before addressing current issue) I cycled the key and then the unit powered up and I had full control, but even tho the a/c came on and I was able to command full fan speed, it was coming out very minimally as if the blend door was stuck midway. (This issue with the fan speed doesn’t matter whether it’s a/c or heat being commanded)
some times when I turn the car on , the climate control is not powered , sometimes works fully but has the issue I stated above , and sometimes the display shows “- - “ and it feels as tho heat is commanded by default.
Just wanted to see if you guys had any issues similar to this or any insight on where to begin looking
thanks and stay safe !
Burning Brakes
Joined: Aug 2018
Posts: 891
Likes: 175
From: PA
Are you sure about the display ? It's not showing three dashes? I can't say this enough. Pick up the FSM and section 8 A that covers the electrical. If it is in fact three dashes that is code 10 or --- per my 91 FSM ( UART OR "E" AND "C" BUS FAILURE. Three dashes indicates data line failure has occurred. Here are two videos on YouTube that may be of help. One is about the codes that can occur and be stored and the other is showing how to clean the contacts if the buttons are giving you problems.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
You have a bad programmer. It's the box just to the right of the accelerator pedal. Basically it has bad capacitors in it usually the 5 volt supply. But all 4 capacitors should be repleced.
I wrote up my whole experience and fix in this link. Or you can just buy and replace the programmer. It does begin as a intermittent. problem.
https://www.corvetteforum.com/forums...-repaired.html
I wrote up my whole experience and fix in this link. Or you can just buy and replace the programmer. It does begin as a intermittent. problem.
https://www.corvetteforum.com/forums...-repaired.html
