1990 Cadillac Battery Goes Dead Overnight and Won’t Start

1990 Cadillac Fleetwood. The car won’t start due to dead battery after about 12 hours. I have had the battery and alternator tested, and they tested OK. There must be a power draw somewhere. Do you have any ideas? The battery and alternator tested OK.

Mechanic JK:
By what you are describing, it sounds like you may have something that is called a ‘parasitic draw’. This is a current and voltage draw on the battery with everything turned off. That is assuming nothing has been left on by accident, like a dome light, or something plugged into the cigar lighter outlet. Be sure to check these basic things before going any further. Also disconnect any non-factory electrical items you may have, like an alarm, remote starter, radio or amplifier.

The way to diagnose this problem is to have a mechanic hook up volt/ohm meter to the negative battery cable. With everything off, check for a draw on the battery by putting the meter on the Amp scale and have one meter terminal on the battery, the other on the cable. If there is a draw, you will see it on the meter. A rule of thumb is that 50 Milliamps is the limit. This can be read as .050 on some meters. If your Cadillac has more than this, start removing fuse one at a time until the draw goes away, or to at least acceptable levels.

Any number of computers or modules in the car can cause your battery drain problem. Most draws will drain a battery overnight, some more severe will take only a few hours. Some common areas on this vehicle to check would be the glove box light staying on, visor or vanity mirror lights stuck on, a power door lock or window switch contacts sticking, trunk light staying on or an internal draw in the radio ETC. These are some things that you can check if you like before taking it to a technician.


1993 Cadillac

My dad has a 1993 Cadillac, cranks great and runs great when cold start, after 7-8 minutes when car warms, just quits, no stuttering or sputtering, just dies til cool again, already replaced control module and ignition coil, bout to lose my mind, cant keep paying shop to put things on with no luck or keep paying to have checked, just an old man on ss, have any ideas?

Usually a problem like that is hard to diagnose, but most times it does have to do with either the ignition module or crank sensor. Those are the two things most affected by the heat of the engine, which usually takes 5-10 minutes to make it die out. If you can I’d recommend getting it scanned for any trouble codes, and possibly using the scanner to watch the live data stream as you drive it to see what sensor is falling off and causing it to die out. Could be almost anything really.


More Car Repair Questions:

4 comments to 1990 Cadillac Battery Goes Dead Overnight and Won’t Start

  • Loubna

    I have Cadillac Deville 2000 I change the battery and my dashboard light is off I can’t see how fast I am going or how much Gas I have any suggestion please .

    Live Chat: You probably blew a fuse while changing the battery. It is quite easy to touch a cable where it shouldn’t go during a battery change. If everything else works fine, check fuses for the interior and/or dash lights. If the fuse is good, you’d have to remove the instrument cluster for further diagnosis and/or replacement.

  • Loubna

    I did check the fuses are good and the AC is working radio working just the dashboard is making me worry , I don’t know if I have to take it to dealer get it check or what?

    If all the fuses are good, then you may have spiked the system and damaged the instrument cluster.

  • This actually answered my problem, thanks!

  • I only became “aware” of this problem last night, thanks to an article about the research ongoing in the Great Lakes in a trade publication, Plastics News issue dated Sept 16, 2013, and have shared my new awareness in my online social networking community “A New Gaia” on Ning. I have shared your website for “want to take action?” there. I am relieved to see your news because we just purchased the Neutrogena Acne Kit for our 12 yr son who is experiencing his first outbreaks because it contains the 2 most recommended as “effective” ingredients. Sadly, I still see “polyethylene” on the ingredients label but at least there is hope !! Thanks for the great work !! BTW our drains go into a septic tank drain field in soil and are unlikely to arrive in the flowing waters of our area . . . or so, I sincerely hope.

Leave a Reply