I had a thread last week asking for help with a climate control module on my '96 C-4. I got some really good advice and excellent instructions on how to remove and clean the contacts on the control module. I did the diagnostic through the temp. control and got a "00" code which means the problem wasn't one of several other things.

After I removed and cleaned the contacts, the problem is still there. No matter what function I put in it, only hot and then cold air will blow out of the ducts. I have to manually set the fan speed.

Ecklers has a control module for $179, but how can I be sure that it's a dead module and not something else? If I take it to the dealer will he be able to tell me anything from any exotic diagnostics he can perform?

So, it is not dirty contacts, although the eraser I used to clean them got very black and dirty. Need more advice and ideas, please.

 

Hey, I haven't heard from anyone yet . Does anybody have any ideas? If I buy a climate control module from Eckler's and that still doesn't solve the problem, will they let me return it?

 

Hey there. I don't know the answer, but my friend went thru this with his 94 with a different ac problem and bought the new one from ecklers. Turned out it was not the problem so he still has the old one. It was a control module under the dash or something like that. I can find out tomorrow..wednesday.
He has the old one which he wanted $100 for. Let me know if you are interested and I will check back here tomorrow. Or better, email me at sirlancair@yahoo.com

 

I have posted this before but dont know if it will help you or not. You might give it a try, nothing to loose.

My C68 worked well most of the time. Sometimes it would put me on ignore and not respond to some of the buttons and the green LEDs might not light as bright as it should.

Ok, so I do this for a living and have no problem going into any of the boxes, but this should be fairly simple for most.

I removed the cover and inspected the solder on the main circuit card. It is well made and coated and the solder looked great. I removed the main board from the vertical board by un-plugging it carefully. I inspected the pins and saw where they could be cleaned up. Also inspected the solder on the smaller vertical board and decided the re-solder the connections on the LEDs. This is a quick re-flow with a small amount of additional solder added. (Be gentle when working on everything and observe some ESD practices).

I used emery cloth to lightly clean the sides of the pins where the contacts are made on the vertical board. Then I used a cleaner on the pins to finish up and blew off with clean air. I also squirted some cleaner into the connector of the main board and blew off with clean air.

I then re-assembled the climate control and installed back in the car. I didn’t know quite what to expect for I felt like I did not do much or really find anything solid.

The system works better than it has ever before. It always responds to me and has been a few days now and confidence is building in the repair. Going down the road is nicer now because the distraction is less due to the buttons work when I now press them.

 

I would not advise using emery cloth on any contacts in any electronic equipment. Most contacts are plated and if you take the plating off you quadruple corrosion problems. Use instead some electrical contact cleaner or a solvent. Using a rubber eraser on solder will make the eraser black and again, do not use anything abrasive on gold plated contacts! The gold plating is very thin and if you remove it, your connection problems will then be much much worse and continous. Wipe gold contacts with contact cleaner or a solvent and a soft cloth. Gold doesn't oxidize or corrode and shouldn't need cleaning anyway.

 

Need a little more info.

Your dash unit communicates with the Processor - called the Programmer - over serial data lines. The Programmer then sends voltage signals to control: Compressor engagement (relay grounded by the PCM); Blower Speed (controlled by a module mounted on the Evaporator Case); and Air Temp (an electric motor opens and closes a door between the Evaporator and Heater Core). It uses vacuum to control other doors, mounted in the Heater Plenum, that open and close to allow air flow to the Heater and/or A/C Vents.

The Programmer also has voltage inputs from the Inside and Outside Temp Sensors. That info is used - when it's on Auto - to adjust Temp Door Position and Blower Speed - unless it's at 60 or 90, at which point the Sensors are overridden and you get max Cold or max Hot along with Max Blower.

The Programmer is linked to the CCM and it's easiest to troubleshoot the system with a Bi-directional Scanner. The emulates the Controls and if it all works, you need new Dash Controls. If it doesn't, you troubleshoot the Programmer and related components. Failing that, there are some manual and visual tests. Starting with your Blower, see what it does at Auto 60 and 90. For airflow, if it's not coming out of the correct vents, check the vacuum source in the engine compartment. If the air is going hot, then cold, then hot again; remove the Blower Module from the Evaporator Case and look inside to observe the Temp Door. If it's flopping around, it's linkage is connected to the motor with a plastic clip - it's probably broken. Post specifics for more help.

 

As usual, another great and informative post by SunCr!

 

Thanks - with some more info, we can probably recommend a repair. I know a lot of the '96's have had problems with the vacuum harness at the Programmer. Just not sure what the real problem is here.

 

I have a 96 and the temp settings do not change - it seems stuck at 60 deg F and the up/down arrows do nothing to change it. It does work from time to time, but lately has been locked on 60 deg. Any ideas on how to fix this?? Thanks.

 

I’m not saying hit it with 60 grit sand paper. The pins are not gold but you can see where the contact has been resting on the pin for 10 years and it looks darkened and dimpled. I understand the concern about plating and corrosion but a little fine emery cloth used lightly sometimes will make the difference. I did it lightly and it worked out well and still going strong. Normally I’d say go with the cleaner to. A lot of these units have catastrophic problems and don’t even come close to working normal.

There is not much to loose as long as care is exercised. The internal pins that join the two boards is the path between the control buttons and the processors (IC chips). At least this check of solder and cleaning is doable by most where circuit components replacements are not. If these minor repairs don’t help the problem, the box replacement might be necessary.