Cadillac Repair: Climate Control Panel, radator, climate control

Question
After reading on your sight about what another persons troubles,(below) and having the same troubles, I went and replaced the computer in my 89 caddy, I installed it, unhooked the cables going to the battery for about 15 mins. and I'm still having the same problem. HELP IF YOU CAN...


The yellow light the says "Service engine soon"
came on as I was driving home, about 2 minutes later the fuel display and climate control panels went out and were replaced with the letter "d" in the middle of each panel which change to the letter "c" after a short time. Now the defroster blower stays on and the fans in front of the radator run all the time even when the engines cold. I have no control over the climate control panel. The car has 150K miles on it and no one had been servicing the car before this happened!
Can you give me any help?


Answer
Hi Big Tee, Which computor did you replace? Were there any codes stored in the engine computor? When both panels display c then disconnect the programmer electrical connector. If the displays are normal replace the programmer. If still shows c unplug climate panel. If normal replace the climate panel. If still shows c plug in climate panel and unplug fuel panel. If normal replace fuel panel. If c then check for open wire or short to ground in ct 713 yellow wire at panels with all connectors unplugged i.e. bcm,fdp and ecc. If both panels show d then the bcm or body computor module is bad and needs to be replaced. So if you replaced the ecm it is looking like the bcm is the computor that needs to be replaced. Hope that helps. Bill