Got most of the bugs worked out on this 1990 model I picked up last week.

AAC has me stumped. Display gives me --- or -rr however you look at it. It blows cold air to defrost and floor. I cannot control it at all.

It will go into diagnostic mode and has no codes.

Radio has been changed and may not be wired correctly.

I switched head units and no change.

I sure don't want to pull the controller out if not needed

 

Check you're vacuum lines. I believe in the driver side . Might just be a vacuum leak

 

 

Can't be a vacuum leak. My display does not show inside or outside temp, can't change fan speed, can't change anything.

 

Ac fuse

 

Just worked thru this in a 94, I was in a default mode to defroster and footwells and the controller would not respond to inputs. While I lack familiarity with the vagaries of the 90 model AC system, and you've checked fuses and vacuum valve as suggested, I think the money's on the programmer. Not real fun to dig out, but replacing the old capacitors was possible for me to do. Check into your programmer.

CliffHarris or pColt may be able to lend further insight.

 

I wasn't going to contribute to this thread, but since my name was mentioned...

The control head just has switches and the display on it. It sends button presses to the HVAC programmer and receives data from the HVAC programmer to the display or to light LEDs. All the smarts are in the HVAC programmer.

I don't know how the 1990 and later cars are configured, but on the earlier cars the A/C fuse is only for the compressor. The HVAC system uses the CTSY/CLK fuse to maintain the settings when the ignition is off and everything else is powered by the GAGES fuse. I think the CTSY/CLK fuse was broken out into two different fuses in the 1990 and later cars. I don't know what they might be named.

 

To get the compressor to run on low freon you do the ctsy and radio fuse. Is that what you are thinking Cliff? Mine is 90 Vert.

 

The 90 is like yours and I have the same symptoms as you. I studied your thread and saw the mention of missing E serial data.

I was hoping the missing stereo was causing it but I might not get that lucky

 

I've had the stereo unit out of mine before, sent it in for some rebuild work, etc. During the time it was out, I was driving it and the AC worked. I just got the theme from Gilligan's Island stuck in my head until I got the radio back in and had something to compete with that tune and shove it back deeper in my consciousness with all the other competing voices now drowned out by better selections of music.
Make sure all your various fuses are good, I think on my 94 fuse #43 feeds the programmer. It's not wrong to check that Vacuum check valve on the passenger side as mentioned as it feeds vacuum to the cruise control as well as the vacuum to the various blend doors, etc on the AC unit, at least that is what I learned for my 94, Good luck on this.

 

You are going to need small tools as shown.
Your programmer will look something like my 88 programmer.
You can see where the 7mm mounting screw goes. You may have to remove the seat or just the seat cushion to get at it. You will need a ¼ inch driver with a long extension to remove the screw.
The 2 tabs at the top slide into 2 mounts in the firewall.
There is a bolt that holds the silicone multi tube block from the inside of the programmer to the backside. The head of this bolt is recessed and you cannot get a socket on it. The only way I know is to remove the very thin press-nut on the tube side which is almost hidden in the middle of the tubes and it is shaped round is by breaking it. Once you pull the electrical cable off you will be able to see it. Use the small screw driver to prize the press-nut up so you can get a hold of it with the small needle nose pliers. Twist the pliers back and forth until you break the press-nut. Be careful of the tubes. This is why you need small pliers. When the press-nut breaks and falls out you can prize the silicone block out of the programmer. If Cliff H. can attach a photo of the hose block it would be helpful. Mail your programmer to batee.com and he will fix it. Send the head unit to him also so he can verify it working properly. Cost is going to run around $200. Don’t buy a remanufactured programmer. I did and the programmer did not function correct so I shipped that programmer to Bryan at batee.com. He’s very quick and good. I now have 2 working 88 programmers.
To re-install you will need a nut to replace the press-nut. My new nut fits a 9/32 socket, small enough to not interfere with the hoses as you attach it. You don’t need the ¼ inch driver just use your fingers to tighten using the socket. Hope I didn’t leave anything out. PM me if you have a problem.

 

The silicone vacuum line block looks like this:



This picture shows how the silicone block is held in place. You can unscrew the press-nut with long nose pliers (and replace it with a real nut):



The black plastic piece has a hex-shaped depression molded into it that the head of the screw fits in. You have to take everything apart from the outside.