Help! I have an electricic control panel heating and air conditiioning panel in my 89 vette and it is stuck on heat

[vettegirl7]

I just bought a 1989 vette and the control panel is not liking me it seems. The control to lower and raise the tempurature was working but it stopped or i did something it seems to be stuck on 90 degrees now ad and it is rather hot!!! How do i turn this sucker down? Someone please help>??? It seems to be the cool button that isnt working, I can switch the buttons from bilevel to heater to defrost to off however it still blows yep your guessed it 90 degree heat!!!! lol What do I order or is there something I can do to fix this myself? Thank you fellow corvetters!!!!

 

[Otter]

I just bought a 1989 vette and the control panel is not liking me it seems. The control to lower and raise the tempurature was working but it stopped or i did something it seems to be stuck on 90 degrees now ad and it is rather hot!!! How do i turn this sucker down? Someone please help>??? It seems to be the cool button that isnt working, I can switch the buttons from bilevel to heater to defrost to off however it still blows yep your guessed it 90 degree heat!!!! lol What do I order or is there something I can do to fix this myself? Thank you fellow corvetters!!!!

I have the same problem on my 'to do' list. Will be following this thread.

 

[vigman]

On my 88

There is a servo that controls the hot / cold flap in the ducting
The rod from the servo connected to the door via a PIECE OF DOO DOO nylon clip
If memory serves you attack it from the pass side have to drop the panel under the dash to get to it

that was my issue.. and I had to fabricate a replacement.

 

[Schrade]

Welcome onto the boards there.

Whatever you do, probably do NOT try switching it back and forth to fix it. If it's STUCK, you can catch the problem 'IN THE ACT'. If it breaks free, you might cause an 'intermittent' problem, which is always VERY, VERY difficult to diagnose...

 

[vettegirl7]

It's a button not a switch. It is the electronic panel one not the o e with switches. Does that make sense?

Welcome onto the boards there.

Whatever you do, probably do NOT try switching it back and forth to fix it. If it's STUCK, you can catch the problem 'IN THE ACT'. If it breaks free, you might cause an 'intermittent' problem, which is always VERY, VERY difficult to diagnose...

 

[vetteoz]

It's a button not a switch. It is the electronic panel
Does that make sense?

The buttons in the HVAC head unit get dirty with age and cease to work.
The rubber pad over the buttons has to be removed so you can clean the switches underneath

Read
Climate Control Button Repair - Corvette Forum

 

[vettegirl7]

Thank you so much I will do that !!!

The buttons in the HVAC head unit get dirty with age and cease to work.
The rubber pad over the buttons has to be removed so you can clean the switches underneath

Read
Climate Control Button Repair - Corvette Forum

 

[mr.beachcomber]

There is a servo that controls the hot / cold flap in the ducting
The rod from the servo connected to the door via a PIECE OF DOO DOO nylon clip
If memory serves you attack it from the pass side have to drop the panel under the dash to get to it

that was my issue.. and I had to fabricate a replacement.

While you may want to try all the other recommended fixes, the one above is by far the most common reason that '89's experience full heat from the HVAC system. I've had two '89's that had this problem as well. The plastic simply gives out with age and breaks usually during the startup servo check which leaves the flap in the open position.

Good Luck!

 

[geekinavette]

If it were a mechanical actuator issue only, the display would change with a press of the temperature button, yet it would still be blowing hot air. Since the commanded temp readout is not changing, there must be an electronic problem (possibly in addition to a mechanical one, but the electronic issue must be resolved first).

Mine did the exact same thing...and it was the buttons just as vetteoz mentioned. Taking the electronic unit out and cleaning up the button contacts took care of the problem.