When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
when i turn on the ac and set it at 60 degrees, it will go to 93 degrees in about 5 seconds. i have tried all the buttons, turning it off and on, even disconnecting the battery. no matter what i do, as soon as i set it at 60 or 61 degrees, it snaps up to 93 degrees and yes the heat does in fact come pouring out!
its over 90 outside and this makes the car tough to drive with just natures ac on (an open window and the heater off)
I don’t know if you have other issues, but after you set the desired interior temp, i.e. 60°, about 5 seconds later the display returns to indicating exterior temperature, i.e. 90° or 93° or something close to actual outdoor temp.
I don’t know if you have other issues, but after you set the desired interior temp, i.e. 60°, about 5 seconds later the display returns to indicating exterior temperature, i.e. 90° or 93° or something close to actual outdoor temp.
I understand that the display will show the outside temp. However, when it displays the 93 degree temp, the heater comes on and pours out maximum heat...even with the ac on!
You may be better off if you pull the HVAC unit (be careful of the plastic fastener anchor points) and send it to ABSFixer.com to have them rebuild it for you. Yes, he does the EBCM too, but he does other things too. He is pretty quick and reasonable in price. Perhaps send them an email with your issue and he may be able to tell you if it is the HVAC control unit or if it sounds like the flappers in the ductwork are not working right. You can also send an email to Lyle at C&S Corvettes and ask him what you may look for to fix it. Both sources are free to ask and they have both helped me in the past. Good luck!
I understand that the display will show the outside temp. However, when it displays the 93 degree temp, the heater comes on and pours out maximum heat...even with the ac on!
Got it. Not intending to be patronizing, by any means, and don't know how familiar you are with our HVAC system, or with how AC systems in general operate.
Somewhat quick and easy, does the AC button switch illuminate and stay illuminated? If it does, that generally indicates at least some level of R134a remains in the system -- though perhaps not enough for effective cooling. Is the hot air common to both the driver's and passengers sides? There are two blend door actuators, and they control the outlet air temperature. If one side is cooler than the other it may indicate a bad or out of sync actuator. Or it can also indicate a lack of refrigerant.
A great first option is to take it to a pro and have a diagnostic check done, particularly if you're not already tooled up (gage set, etc).
An extreemly helpful thread from the past: https://www.corvetteforum.com/forums...post1561996844
Ken, it's not possible to set the system to 93 degrees. The highest it can be set at is 90. The 93 degrees display you're seeing is something other than what the system is set at.
Take a look in your owner's manual and do some testing.
Are any of the buttons stuck? Do all buttons work? What happens if you rotate the left dial to room temperature, does the fan stop as if the car has reached the desired temp?
I wonder if maybe your temperature sensor is bad or disconnected?
Do you have a scan tool?
It's helpful in general to know what year and model?
Last edited by Dads2kconvertible; Aug 1, 2025 at 10:50 AM.
redzg
i realize that the 93 degree indicated is outside temp, but when the display switches to the outside temp it turns the heater on full temp. the ac remains on as well at the same time. the ac does appear to be fully charged as it blows very cold and stays on. all the buttons seem to be working as designed. if i dial back the temp **** to 60 degrees it will shut the heater off until it once again displays the outside temp and then the heat turns on full blast and the ac stays on!
Help - heater.ac
