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1999 SLS with electrical issues? Stumped for a month help!

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Hi all,

I'm hoping someone can assist me with an issue I'm having with a 1999 Cadillac sls. First off, when the car is not driven for a few days it is stone dead. Will not start. No lights, nothing. I replaced two alternators and the battery. Issue still keeps happening. Now when I have the car running the security light and battery light stays on. I took off the rear seat to check the fuse box and there is a light blue wire and a black and white wire cut. there are so many wires i dont know what these go to. when i put the wires together with the power probe battery light stays on, and security light comes off. when i put the power probe to the black wire with no power or ground the battery light comes off. I am so stumped. I spoke to customer service and the guy ran the vin, said there "may" be a recall and a bulletin on the vehiclel but was unable to tell me what it was all about. When i call the dealership they say nothing comes up, but it "may" be an inline jumper harness short? I never even heard of this. Im at an impass. I hope somebody can shed some light on this. Thank you!

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Don't know on the '99....but earlier Cadillacs had a 'no charge' issue with aftermarket alternators. Did you have a GM Delco unit put in or aftermarket?

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Is the alternator actually charging, overcharging? There is a ground on the LF framerail underneath the air filter/PCM housing case, relocate that ground to the stud nearby. The stud will be located on the inner fender well and the harness will reach just fine. When you try to remove the bolt for the ground it will more than likely be rusted and snap in half in the frame rail.

I remember a black wire from the battery negative cable that is a resistor for the batttery light coming on for a overcharge issue.

Is the wire broken or even in place under the rear seat?

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The first thing to do is repair the cut wires that you found - If both ends of each of the wires are visible, it should be a simple task of reconnecting them.

Connect a battery charger to the jump terminals under the hood while troubleshooting so the battery does not go dead.

To isolate a parasitic drain, disconnect the negative battery cable and install an ammeter between the negative battery cable and the negative terminal of the battery. A digital voltmeter that can measure up to 10 amps will work. Connect the negative lead to the battery and the positive lead to the disconnected negative cable.

After the PZM "goes to sleep", begin removing fuses until you find the circuit that reduces the amperage draw to less than 30 mA (.03 Amps). Once you isolate the circuit that is causing the draw, install the fuse and begin disconnecting the various devices on that circuit until you find the one that drops the amp draw to below 30 mA.

'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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the wire is broken.... just two open wires. so, since i posted, the car has not gone dead I just cannot figure out how to get the lights to go off on the dash. It says battery not charging. I changed the alternator twice. The first alternator was at 17, way to high, the second i put in is reading 14. Thank you for the advice, I'll give it a whirl and update!

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