Auto Tech Help (Cadillac specifically)

Any Cadillac gurus out there?

I have been experiencing some issues with my 98 deville which sources could not be found by cadillac's built in DTC menu.

All of this happened suddenly:

The interior lights cannot be turned on all together at the dash switch, the headlights can not be manually turned off or on, the ac/heat display has gone away and been replaced by two dashes where the temp should be, and lastly, the gear selector lights stay on even after you turn off and lock the car. Then the battery dies because something is keeping the gear selector display running and possibly more stuff I don't know about.

Being short of my daily driver and having my mustang without engine right now has kinda put me out in terms of transportation.

If anyone has had a similar problem and fixed it or knows how to fix it please tell me what to do!

Knowing practically nothing about car electrics and absolutely nothing at all about car computers, so this likely is a complete waste of time, have you disconnected the battery and let the car sit overnight?

If all your problems began at the same time, maybe it's the computer/chip controlling all that stuff. Disconnecting the battery for more than a few minutes might reset the thing.

Actually its all of this stuff that kills the battery in the first place. So I have been disconnecting it every night. Till about an hour ago, it seems that it may have something to do with something attached to the "components" fuse, because now when I disconnect that fuse everything turns off and the battery doesn't die.

I also ran the DTC (integrated diagnostics) and reset the computer chip through that.

That did nothing. So now I have a car that still doesn't work and I have to disconnect the "comfort/component" fuse at night and reconnect it to drive.

Its all very disheartening as this is yet another issue I am experiencing with this car. It seems as though its doomed. I had a board fly off of a flatbed and sail through my winshield about 20cm from my face, glass shards all on my face and hair. Then a few weeks after that the radiator suddenly burst and was leaking all down the road. Fortunatly I was able to get home. I think these are all signs that we should not have taken my grandpas car away.

Found this on a forum from 2005, but it's hard to believe. (Included it in the interests of science. )

If u read some of the other posts here u'll notice that all the people who are having weird electrical problems have their factory radio taken out. I believe that part of the factory stereo has something to do with the car's electrical system itself, so removing it will cause problems.

On my way to figure out how to rehook the radio and have my CD player working...

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But then I came across this.

Date: 2/22/2008
Subject: '98 El Dorado & problems w/after market radio

Question
I just had an after market radio installed and now the car will not start. Is it the anti theft device causing problems?

Answer
YES, SIR. WHO installed the radio ?. There are various voltagea going into and out of the original radio such as 5 volts, 12 volts and 16 volts. If you accidentally hooked up the wrong wires you can blow the computer and or engage the ant-theft system. Have a professional radio installation facility test it for you.

There is no way for me to know what is wrong without seeing how it is wired.

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This sounds like a similar plague of electrical problems, but with an answer. It's too long to quote (and who knows whether it's accurate).

milessthomas said:

Till about an hour ago, it seems that it may have something to do with something attached to the "components" fuse, because now when I disconnect that fuse everything turns off and the battery doesn't die.

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The web search I used was "1998 cadillac de ville" "electrical problems"

It also turned up a Q&A that I can't find again, about the car battery being dead in the morning. The suggestion in the answer is the auto-levelling rear end is continually running because of a leak in a shock or the compressor. The answer guy said to check the rear end in the morning when the battery is dead to see if its too low. (I had a '92 Roadmaster that raised the rear end, so maybe. . . .)

Thanks for all the info Brown Study! This is quite a good start to my search, but unfortunatly all of those people talk about replacing their radios, I still have the stock bose system, but it may be the theft system.

Again thanks a lot.

I just got done pulling the radio (stock) and left it out and drove it. Turned the car back off and reset the theft system. Still going. So my next venture will be that Illumination relay and RIM module. If that doesn't work, yanking the factory alarm out.

Goto cadillacforums.com and sign up and post your question under the deville forum.

This forum has become a great resource for me as I own a couple Escalades but do not own a deville and cannot answer your question.

The caddy gurus on this forum are amazing.

Hope this helps!

Producerman

yikes!

i had a 93 eldorado that had it's ignition system self destruct along with the casing on the starter (which for some odd reason lived under the ignition piece on top of the engine rather than hanging off the bottom/side).

cost A LOT of money to get that fixed. about triple the same bill on any other car i've owned.

good luck and watch your pockets!

Thanks for all the help guys, I figured it out, ground wire snapped. After replacing it everything worked fine again.

producerman said:

Goto cadillacforums.com and sign up and post your question under the deville forum.

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Did that about a week ago they had never heard about this issue and told me to do stuff I have already done.

eric said:

yikes!

i had a 93 eldorado...

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Hearing that almost killed my hopes as I'm looking for a 00' eldorado right now...yikes is right