All of a sudden I can not raise the temp on my electronic air and it still is cold in Wisc. yet. If I dsiconnect the battery it will reset to 75 degrees, but I can only lower the temp and not raise it. Any ideas would be appreciated as I hope I don't need to replace the control as they are not cheap. I have tried to do the diag codes and when I push the up and down arrow keys together all I get is that it counts down to 01 and that's it. Any more ideas would sure be appreciated.



[Modified by lee.anderson, 11:36 AM 5/16/2003]

 

Take the control box out. Open it up, clean the contacts with contact cleaner from Radio Shack. Worked on mine

 

Lee try this procedure to see if it will "self diagnose" itself.

BTW, Credit is given to the author at the end of the procedure.

--------------------------------------------------------------------------------------
Displaying A/C error codes
To enter diagnostic mode (Built in Test):
Ignition Key On, engine off Push and hold the fan up arrow & fan down arrow at the same time. After about 5 seconds, the LCD where your temp/fan speed is displayed will show "-00". Push the fan "AUTO" button, and the LCD will display any fault codes stored in the programmer.


Fault Code Description

00 no faults detected

01 Temp Door Motor Circuit Failure

02 Temp Door Motor Circuit Failure

03 Ambient Sensor Open

04 Ambient Sensor Short

05 In-Car Temp Sensor Open

06 In-Car Temp Sensor Short

07 Solar Load Sensor Open

08 Solar Load Sensor Short

09 Low freon detected

10 or --- UART Failure


Push any lower button (ie vent, heater, AUTO, etc) to exit the diagnostic mode.
FYI, pushing the fan up arrow or down arrow while in diagnostic mode, followed by fan AUTO, allows you to check other parameters as well. However, I'd need a few more pages to explain everything.

Jim Mason
90 L98 - 6 spd - Z51

 

Jim, would it be possible for you to scan the pages in the service manual that refer to all the parameters you can check like you said above?? I would be very interested in this data if you could do that for me.... :cool:

 

Wheelman,

I'm not the originator of that article. However, I do have a service manual that is probably where it came from.
I'll check tonight when I get home and if I have it will get it on here.

 

Thanks for all the replies, if I get an error code is it possible to fix this and if so how ? I have no problem taking it out to clean contacts or ??? but don't know exactly what to do or how once it is out.

 

Hi Lee,


Looks like all the codes refer to devices EXTERNAL to the controller except number 10..... UART defective. That would be inside the controller itself.
Number 9....Low Freon Detected, is not the problem because it's blowing cold air.

So, only a few things left, if it will self diagnose.
If it won't do the diagnosis it's probably the controller itself.
I've never cleaned the contacts in mine but there is a post pertaining to that above. Hmmm maybe he knows what to look for.

Will check my service manual for more tips tonight.

BTW what year is your Vette, Lee?
Will a controller from a 91 fit it by chance? :)


[Modified by VetNutJim, 2:38 PM 5/15/2003]

 

Vette is a 1988 and I have been told that the electronic control is not even available any more. I sure hope there is a fix or I will be watching Ebay or asking here who has a good used one, can't go without that temp adjustment.

 

Lee,

Do you know if the 91 controller is the same as yours?
Anybody else know?

 

I believe the controllers changed in '90, so you need one from '89 or earlier. Contact The Last Detail shop in Tucker GA, They have them for '88-'89 C68 A/C for $230.00(?) as an exchange unit. Before buying a controller, Drop the passenger side hush panel and check to make sure the Temperatur valve motor is moving the temp door as you change the temp settings on the controller. My '89 Service Manual indicates that if there is a "system Fault" the EXT TEMP indicator will flash for approx 60 sec after IGN ON occurs. It sure sounds like a controller problem though.

Hope this helps

 

If replacing the head unit doesn't help (or cleaning the contacts-I think 65Z01 Jim has the procedure on his website)
maybe check the vacuum controller:


do a search for a topic called "SOB A/C controller leaves me in the cold"
by author 89paulincal(me) in C4 tech archives for the details on the values of the replacement resistors and procedure
Lemme know if need additional help, as you should check the door operation first.
Oh, yeah, is hot coolant getting to the core? Has system been cleaned?


[Modified by 89 Paul in Cal, 6:20 PM 5/15/2003]

 

ttt