Bobby 3/17/2010Start at the fuse panel, find the fuse for the heat and a/c circuit and pull it to see if it has blown if it has replace it. If it blows the fuse again there is a short in the electrical circuit and will require some testing to find out what is causing it. If the fuse is good, you might want to start by checking the control unit itself.
92bimmer 3/17/2010Thanks Bobby.....i have checked the fuses and they were all good. I have the bentley service manual for this but it does not tell me a way to check the problem...like a troubleshooting guide. It shows how to pull the control unit(has the on/off switch) from the dash and then it gives me something completly different that is listed in the index as a "a/c control module" that is buried under the dash. nothing saying how to know which is part it could be or how to tell if they are good or bad. Any thoughts?