Eldorado battery drain

I hooked a 12 volt lamp between the Pos. battery post and the large battery cable, which I disconnected and the lamp lighted pritty bright. I disconnected the hot wire to the alternater. It’s not the problem. But, I found that when I pulled a large 50 amp fuse listed as body 3, the light went out & the dain is gone. I need to know what is on the body 3 circuit. No lights are on, interior or exterior. The key is out, the glovebox light, trunk light, and trunk opener are disconnnected. If I had a schematic for the body 3 circuit it would be a great help. Or, can you lead me to where the problem might be?

Odds are there’s a hot wire that’s chafed away and is grounding out, but tracing exactly where could be a pain in the butt. A Haynes/Chilton’s manual should have wiring schematics in them; start at the fuse and work your way from there.

I looked at data for a '99 model since you didn’t state the model year for the car.

That fuse ties to a lot of things in the rear compartment fuse panel so I would check those fuses next and do the same testing to see if you can get closer to the trouble.

What year, 1952, 2002 or something in between? Seriously, if someone here can’t help, find a Caddy forum. If you are in a real hurry, buy a subscription to AllData.com. They have good diagrams. You might be able to log in to a database at your public library.

Yes, a circuit diagram with the Eldorado would be very helpful. Some times you can get it out of Alldata. Some librarys give you access to this service. Chilton and Haynes manuals have wiring diagrams but check before you buy. Of course, the OEM service manual will have the schematic but will be quite pricey. That 50 amp fuse probably feeds a bus with a lot of other fuses feeding individual circuits so you might find those other fuse boxes and start pulling fuses until your test light goes out.

This is the hard part of trouble shooting without a schematic. Good luck.

You are correct Researcher. It ties to the rear compartment fuse panel in the data I looked at for a '99 model.

I traced the 50 amp fuse circuit to a fuse panel in the trunk. I narrowed it down to a 30 amp fused circuit that has the chime, electric windows, radio console fuel door & trunk opener so far. I removed the door panel and disconnected every electrical connector but, the drain remains. I’LL y the library to see if they can lead me to an electrical Dia.for my car. I’LL keep you posted.

This might be useful…


IT’s Aa 96 Eldorado. I got an electrical schimatic for my car at the libaray. It seem that I have checked every component in that circuit. So, my final conclusion is that mabe, just mabe the PCM is the problem. How can I check it out?

If you have a Bose audio system with speed sensitive volume control disconnect the unit and recheck drain. Please report back.

Hi Stanker, Right on!! I removed the radio and when I unpluged it, the drain was gone. Is it costly to repair?

Using a ampmeter instead of a test light will give you data you can use to draw a conclusion. Basic electrical system knowledge a schematic and the proper test equipment are keys to electrical diag. and efficent (in use of time) repair. How many amps was the radio pulling? Using the test lamp method is very oldschool.

Does the speed sensitive volume control function work properly?