I have a 1995 Concorde with ATC. Recently, the power to the heater/AC control panel seems to be intermittent. One day it works, the next you simply get whatever settings the control panel was left at before the power failed to it. The heater fan still runs and it seems to be working in the background - just no control. The fuse is OK, I have performed a complete reset and recalibration but it makes no difference. Anyone have any ideas?
Are you sure it keeps the last working settings? There's actually a safety feature on the control unit so that when it dies it will blow hot air out of the windshield defrost vents. I don't know what the exact problem is, but mine has been acting up lately. A good, hard slap to the left side of the unit usually fixes the problem for a short time. As for a more permanent fix, I'm lost.
Your ATC going bad is a common problem. Look on EBAY for LHS ATC There is a guy on there that rebuilds them after time they have some common failure parts inside the ATC. I bought one for the buy it now price for forty something dollars sent him my old when I got he new one and it's warrantied for a year. Got fast shipping and a good ATC. His email is firstname.lastname@example.org
Hope this helps
Yeah, I have three ATC units including my original which I am using right now and all three of them have that same exact problem. I was just giving it a slap and then it decided it was going to get back at me by taking almost busting my knuckles on it to get it to come back on. I have cracked the shit out the the lens next to the temp knob. Most of the time now it takes a good hard hit for it to come back on, very rarely will it only take a light hit. I finally got tired of hitting it the other day and after hitting it once it went right back off and I said the hell with it and let it go and it come back on after 15 seconds. If I would have had a screwdriver it would have been taking flight lessons that day!!!!!!
i had that same problem i took out the atc unit then took off on the rear of it the black square plug in relay then wipped it off the contacts then plugged it back in and has worked with out fail since *Shrugs* so thats the problem with the unit i saw them for cheap if you put in the numbers in a search engine they are like 12.00 dollars from some company that has the relay on like 6 months back order that makes them so i was like omg. but mine worked when i cleaned its contacts.
With mine I took it apart and touched up all the solder connections to the plug. I also made the connector between the front and back board somewhat perminant (sp) by soldering the pins to the front board. Since this fix it has worked flawlessly for a year and a half.
Hmmmm, I am interested to find out what these people on eBay are doing to fix the faulty units. Soldering the pins to the front board sounds like an idea since you only need one side to come apart to disassemble the unit.
I wouldn't think the relay has anything to do with the head communication failure, correct me if I am wrong, but I am pretty sure the relay is for the rear defrost. Every time I turn the rear defrost on and off I hear a click which I am almost positive it is that relay. When my unit goes out it is usually when the rear defrost is off.