Cadillac starting troubles, again!



My wifes 2000 Cadillac DHS is giving us trouble again with intermitent starting problems and I need some input on what it could be. We were about to leave the house this evening when the car would not start. The car seemed to have plenty of battery power, it is new, but whould not engage the starter when you turned the key to start position. A quick test of the battery proved it was good so I began to look for other posibilities. I noticed with the back doors open the dome lights didn’t work so I thought maybe a bad fuse could be the problem. So, I started pulling and checking fuses and all were good until I pulled the fuse in the #18 slot of the fuse panel under the seat. On the diagram it shows this fuse as right rear door module. When I pulled it the dome lights instantly came on, the gas door popped open, and the trunk popped open as well, and this fuse is not blown. I tried to start the car with the fuse out and it fired right up and everything appears to be working, other that the dome lights when you open the back doors. If you put this fuse back in the car will not start and there are several electrical issues with dash lights and warning lights.

Obviously there is a short somewhere, probably in the rear door area, so my main question is what is a “door module” and how could it cause so much trouble with the car.


Unfortunately, the marriage between sophisticated electronics and common automotive functions has NOT been a very happy one. Whether the dome light comes on when you open a rear door is NOT important. Having the car START when you turn the key IS important. You are to be congratulated for solving this problem!! Many professional mechanics, including those employed by Cadillac dealerships would have torn the car apart trying to find it. The wiring diagram of a modern cars looks like one for a pin-ball machine…Drive on…


Thanks Caddyman for the kudos. You’re right about the wiring diagrams on these new cars, most look like something from the space shuttle! I just lucked into the fuse discovery and was floored by the fact that, by removing an un-blown fuse, the problem would clear up. I always thought that if there was a short in a circuit the fuse would blow so I was looking for a blown one. I’ve just about had it with this cars little “quirks” and am about ready to sell it for scrap! Do you have any idea what could be causing the problem? With the fuse out I have no power door locks or power window functions on both rear doors and apearently no switch function that signals a door being opened. Do you know what is included in the #18 circuit? I quess the wife could drive it like this but I would like to get it fixed, so I can sell it!!