1997 Eldorado 4.6 northstar

[detroitphil]

i have a 1997 eldorado with 4.6 northstar car has 117,000 miles after replacing alternator and radiator last week now my battery wont hold charge overnite! i have checked charging system and replaced battery twice! now im hearing of phatom electrical shorts? anybody ever heard of this?

[BodybyFisher]

First check for codes, look for alternator codes

Have the battery load tested, and clean battery terminals/connections

Any aftermarket audio, amps etc?

Then in a dimly lit area, state pulling fuses with the key off car sitting for 10 minutes, doors closed, and look for a spark at the contacts, that will be the circuit that is causing the problem

Check trunk light, glove box light, vanity mirror lights,

[Cadillac Jim]

The car has two electrical circuits that time out after about 10 minutes of the car sitting undisturbed, the RAP (retained accessory power) and the "inadvertent" power which provides power for the interior lights and such. The difference is that the RAP stops when a door is opened with the key off, while the inadvertent power continues regardless.

If you have a power drain problem it can be caused by the inadvertent power staying on or by something on an always-hot circuit being on when it shouldn't. I have a friend with a Toyota that has a problem with the trunk popping open and the light in the trunk draining the battery; he pulled the bulb until he found it. The Cadillac puts that bulb on inadvertent power to prevent this kind of thing, but if it's caused by the fob getting its buttons pushed in the house, which will turn the inadvertent power back on each time.

Looking at the main battery power distribution on page 8A-10-1 in the 1997 FSM, the battery is connected to the LH and RH Maxifuse ® blocks, the starter solenoid, and the alternator; these are the tree red battery cables you see on the positive terminal of the battery cable. If you have a bad alternator diode, that will cause battery drain (I once knew someone who had this problem on a sailboat) but that should throw a code on a Cadillac.

The RH Maxifuse Block has these fuses on it:

• BATT 3 (30 Amp)
• Batt 2 (30 Amp)
• IGN 1 (40 Amp)
• BATT 1 (50 Amp)
• Brakes (50 Amp)
• Cool Fans (50 Amp)

The LH maxifuse block has these fuses on it:

• Body 1 (60 Amp)
• Body 2 (60 Amp)
• Bode 3 (50 Amp)
• Indvert (50 Amp)
• Lamps (60 Amp)
• Ign 1 (50 Amp)
• Windows circuit breaker (30 Amp)
• Seat circuit breaker (30 Amp)

The simplest thing to do is to leave the car with the hood up and the key off, with the fuse cover off (the big one that exposes the Maxifuse blocks, not the little one that shows about 10 fuses) and pop each of them in turn. If a 12 Volt test light shows that one of these is drawing power after about ten minutes, then something is amiss on that circuit.