91 Vert

I have studied the archive posts in detail so I know about taking the unit apart and cleaning the contacts with an eraser and alcohol and I am going to do that.

I am not sure if that is my problem. I have various buttons that don't work depending on which day of the week it is or what color shirt I am wearing. On Tuesday the OFF and DEFROST buttons would not work at all. Now today they are working perfectly and the temp down isnt working. It almost has a pattern. It seems like if I push buttons in a certain order, some buttons will work and some will not. The next day it is a diffrent group of buttons that will not work.

Could this unit need more than cleaning?

I know this sounds confusing but I am just as confused.

Any help is appreciated.

 

Don´t want to sound ignorant, but have you checked the system for fault codes?

Press and hold down the fan up/down buttons (if possible) for 6 secs.

Hopefully you get 00, if you get 09, you are low on freon.

Reason I state this is, that I had exactly the same things happen including an outside temp that didn´t match the real world.

Fixed the leak, filled up, and reset the system (dis-reconnect battery), and all is fine now.

Two years ago, and all is still fine.

Just a thought...

 

Generally faults have nothing to do with whether or not something responds when you push a button. Your Year does communicate with the Processor - Programmer - over serial data lines, so if the info in the Controls is changing when you push something and the response isn't what it's suppose to be, I'd suspect the Processor or those data lines (especially if I had mucked with something like the radio or anything in proximity to the HVAC controls behind the dash). You might, just to be sure there isn't some processing glitch, reboot the thing - disconnect and reconnect the battery. Otherwise, I'm dangerous with a soldering iron (sometimes wrenches and screwdrivers and definitely chainsaws), so if it were mine, I'd check power and ground and if they're good, replace it - or the Shop Manuals call for the use of Bi-directional scanner. With that connected via the CCM link, it will emulate the Controls and if it all works, it's a pretty good bet it's the Controls. I'd guess shop time for that is about an hour (isn't it always at least that?) though it probably takes no more than 5 minutes and the real problem might be finding a Dealer with right Cartridge for the Scanner.

 

Before my air was repaired I had the 09 code. No codes now.

 

The functions of the buttons work properly when the buttons work.

 

And when they don't? Ie, when you lower Blower Speed from 10 to 1 does the Blower stay at the 10 speed even though the Controls say 1 or does it just stay at 10 no matter how hard you pound on the Fan Speed button? If the former, I'd say it's a Processing or communication problem. If the latter, the Controls.

 

The Latter

 

a climate control controller unit up under the dash (up above the accelerator) that is really the 'brains' of the C68 system. The head unit with the buttons is kind of like a remote control to the 'real brain', the controller unit.

If you have a FSM there is a full troubleshooting procedure chart in there which should point you to the proper place.