I was hoping someone here could point me in the direction of how to fix an hvac controller problem on a 1991 corvette with the automatic climate control.

First off I want to say this car is not mine. It is someone that my father knows and they are having trouble trying to figure out the problem and asked if i could help. I searched around a little bit but i haven't found anything definitive as far as what the problem is. I thought it might have been the control head but I was told the owner has already installed a new control head.


Here are the symptoms listed:

Unit stays in Auto Mode

It says no fan motor

Sometimes you are able to change modes but the unit keeps switching back to Auto Mode

Once is switches back to Auto mode the owners says they cannot take it out of auto mode ( I'm unsure if shutting the car off allows the owner to change modes again.

It had codes 2,4,6,8 listed but then they are crossed off my list here but the owner says the codes clear themselves and it goes back to reading 00.

When the unit is off it will occasionally turn on and go right to auto mode. It appears it will do this multiple times until you shut the car off then they say it starts all over again.


I'm assuming other people on here have had similar trouble which is why i decided to post it here. I'm not familiar with the in's and out's of all the C4 electronics.

Any help or suggestions are appreciated.

As stated above for anyone who missed it the owner did say they put in a new control head. I don't know whether it was new or used or where it came from so there is always a possibility it is bad. Being some of the parts are expensive I don't want to just tell the guy to throw parts at it.

Thanks

 

These units sometimes have contact problems with the internal connectors. There's a thread here that deals with fixing this:

http://forums.corvetteforum.com/c4-t...-for-88-a.html

 

Thanks for the heads up on that link. In another thread I read where someone suggested the control head someone mentioned it may just be a problem with the contacts. The didn't have any pictures in that thread so i didn't quite understand how it actually connected.