Digital Dash Problem

[opelgt19]

Hello all and thanks in advance for any replies.
1989 Deville : no digital readouts, fuel/speedo/climate controls
everything was working, then nothing one morning.
no controls seem to respond on climate control/blower.

checked BCM fuse and re-seated
re-seated BCM connections
is the power for the digital displays all through the BCM?
or is their a relay or another fuse?

[JJhomer83]

Originally Posted by opelgt19

Hello all and thanks in advance for any replies.
1989 Deville : no digital readouts, fuel/speedo/climate controls
everything was working, then nothing one morning.
no controls seem to respond on climate control/blower.

checked BCM fuse and re-seated
re-seated BCM connections
is the power for the digital displays all through the BCM?
or is their a relay or another fuse?

http://www.cadillacforums.com/forums...1571#post51571

don't know anything about your problem so maybe this will be more helpful

[opelgt19]

thanks, i saw that before but my entire digital displays suddenly
went out fuel, climate control, and speedo so it logically has
to be a common connection to them all,
i have another fuel guage display and climate control and they
do the same thing, yet they worked before in the
same car. i've traced wiring as best i could and none have power to them.
i saw or read somewher the BCM supplies power, but in another post
someone said there was a power relay??????

[carnut]

Had the same problem on an 88 DeVille. Was a shorted BCM. Bcm is located behind the glove box. Remove the glove box assembly to access. I replaced mine with a used one from a pick-n-pull wrecking yard. Hope this helps, Bill. post your final repair so others can learn.

[opelgt19]

finally found a bcm at a local pick-a-part yard, supposed to be good.....
just tried it and still have the same problem no digital display on the speedo, climate control or fuel data displays.
i know that the used one could still be bad but i have the feeling i'm overlooking something. i have some wiring diagrams but they are not very detailed. i noticed when i turn the key to the off position all the displays light up briefly.
any ideas??????????

[richp85]

I HAVE THE SAME PROBLEM REPLACED THE FUEL DATA CENTER AND CLIMATE CONTROL CENTERS BUT NOW WHEN I TURN THE KEY READINGS COME ON FOR A SECOND BUT STAYS BLACK IS THERE A FUESE OR RELAY SOMEWHERE OR DO I RESET THE COMPUTER BY UNPLUGING IT:

[chinyocka]

opelg19 did you ever find out what the problem was. i am going through the same problem with an 88 deville. been working on it for a month now . back is shot, wife is miserable and sweating down here in florida with no air. your response would be greately appreciated.

[shlep0069]

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

[tracy]

I havc the same problem on my 92 Deville. I replaced the BCM with used and the Speedometer will light up until it is started then seconds later all is off. I replaced the BCM with a new one frm dealer making sure to install the original PROM. Everything came on, including fuel monitoring, climate control and speedometer! I thought it was fixed. Then the new BCM got hot to the touch and 5 minutes later the air conditioning quit, followed quickly by each dash display until all were off again. When the BCM cools, it all works again for about 3o seconds.
I have read of the Central Power Suppy causing this problem. But will it cause the BCM to overheat? If not what will?
thanks

[tracy]

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

[hthorn]

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.

[shlep0069]

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:

[alwaysfishin]

Originally Posted by tracy

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.

[DrtyBrd]

Originally Posted by shlep0069

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.

[shlep0069]

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