There is a seperate wire on the + terminal, which must be the supply for the BCM. I say this because I once replaced a battery, (on an 88 DeVille) had an identical problem, then I cleaned the terminals, and it all lit back up. Test for charging voltage; if your alternator's pumping out 15+ volts, that could account for the thermal failure. Pull the (-) terminal off first, then remove, inspect, and clean ALL of the (+) terminals. When you reattach them to the battery, turn them slightly as you tighten them, as this can improve the contact. The only other reason I can think of might be a defective ground; a Mitchell/Alldata wiring diagram will show you where it is. A Haynes or Chilton may help, it may not...worth a try though.
Well, my dilemma is still continuing. I re-checked all of the grounds as suggested by my local caddy dealer. yup...they are all still ok. I have continued to read into similar problems and read a post about the vats module/wires going bad. Seemed like a good idea since when i try to crank the engine the security light just flashes and dinger dings. I made up a resister package as described and made it match to the reading i got across the key.. Cut the wires and spliced in the package. still no cranking and the security light still just flashes at me when try to crank. About ready to find a cliff and push:bangh ead:
I went to my service manual and found all the fuses that go to the BCM and pulled them one at a time. (25, 16, 7, 4). Fuse #4 is the circuit that causes the BCM to overheat. I am having trouble finding a wiring diagram for this circuit. Can anyone suggest wher to find one. It is not in Chilton.
thanks
am having same problem on 1986 deville, blower not working and instrument lights not working.
I have a nightnmare of my own that is very similar to the problems you guys have been having. 1993 cadillac deville 4.9L Here is the story. Had a bad oil leak that required removing the trans. Fixed the leak and reassembled car. When I 1st went to start the car the dash lights worked and everything seemed fine. I shut car off to check oil and restarted. NO DASH LIGHTS, NO FUEL GAUGE, A/C DOES NOT RESPOND!!!! Pretty much all of the same things you guys said. Checked for loose grounds or any plugs under hood i forgot/missed and found none. I did not have time to dig into it further so drove the car with no dash lights. New story!! Now after 2 weeks of driving the vehicle does not crank. I have no power at the crank fuse, the ecu fuse and one other fuse that I cannot think of at this time that is under the dash. I work at a ford dealer so i talked to a service guy at the cadillac dealer near me. He seems to thing that I do not have a good ground somewhere or that the starter connections are not making good contact. NOt sure.. getting back into it tonight. will post back what i find
Weird you should say that. I took my car in to the dealer for an oil pan leak and they dropped the entire cradle, got it back together and the dash didn't work. According to the tech and service advisor there was a plug under the dash on the drivers side (up by the driver side tweeter) that came loose. They got that fixed but now I have a VTD B3055 code and security light that I cannot get rid of. Car starts and runs fine but I wonder for how long.
I had to drop the cradle and trans to get to the by-pass tube that went up through the block to the remote filter housing. similar job though. You have to driop the cradle to do th oil pan. Do you know what the connection was to?? Was it into a module or was it a ground?? I will look awhile by the tweeter to see if i can see something but fixing an oil leak in the engine should not cause this problem. I still feel its a coincidence. i am so sick of this car i plain out stopped looking at it
