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2005 STS 4.6
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6 Posts
Discussion Starter #1
How's come I can pull every single fuse and my power draw is still present I unhooked the electrical box under hood and then it will still draw. It won't stop drawing until I unhook 5he alternator I changed the alternator and still have this issue. The car is a 2005 cadillac sts. North star eng.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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67,978 Posts
Does your vehicle also have an under-rear-seat fuse/relay box?

The car also has RAP - Retained Accessory Power - that keeps a bunch of stuff powered up for 10 or 15 minutes after Key:OFF. The 12 volt power ports are hot either during RAP or at all times, depending on where the port fuses are set.

Any time you open or shut a door the system powers some stuff up for a while...........

What happens when you disconnect/connect the battery cables at the battery - negative first off and last on?
 

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2005 STS 4.6
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6 Posts
Discussion Starter #3 (Edited by Moderator)
  1. It does have that fuse box youre speaking of there's 2 actually behind both front seats under the rear. As I tried to localize the power draw I disconnected the box under the hood which should not send any power onside the car should it? What I found was the power draw was coming from the alternator. There's 2 red cables one comes from the alternator and starter and the other to the fuse box. With the box unhooked my power draw is a full volt of the battery 12 or 13v. Thank you so very much for your help. And to answer your question while hooking up the battery I believe I've tried what u asked and after it sits for 20 minits or more the cable snaps so theres quire the draw.
If I unhook the alternator it goes away for the most part. Only 5 volt draw after that. Will the alternator feed back? I put a different one on but same problem
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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67,978 Posts
I assume "the cable snaps" refers to a spark when you reconnect. The red cables are 12 Volt + wiring - the one from the alternator goes to either a large fuse box connection or directly to the battery - that's the charging wire that carries current "from" the alternator. Reverse current - from the battery to the alternator guts - is blocked by a diode pack in the alternator voltage regulator: current can travel only one way - from the alternator. The red cable that goes to the starter motor carries current "from" the battery to the starter upon demand (starter solenoid).

If you get a spark when you reconnect the battery then it's either because RAP is still active or there's a short to ground somewhere in the car - and the "somewhere" is the big question.

Battery drain is not measured in volts - it's measured in Amperes or milliAmperes. 0 to 15 Volts is system voltage, sort of like water pressure. Amperage is power - how far open the faucet is. 10 milliamperes is a slow, slow, slow drip; 150 Amperes is wide open.

To measure battery drain you insert an ammeter in series with the main red cable: battery > ammeter > cable > electrical loads.

All our cars have a residual (parasitic) amperage drain of 5 to 30 milliAmperes - that keeps the electronic memories active with the engine off. In good condition the car's electrical system/battery should still start the engine after a month of sitting idle.
 

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2005 STS 4.6
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6 Posts
Discussion Starter #5
I have a fluke multimeter it does amps but is only a 10 amp max I've tried to check the current draw but got nowhere. I have disconnected the outside fuse box so that I only have the one red wire from the battery to see if that was where my draw was coming from the only wires hooked up was the 1 wire that goes to the starter and then to the alt. And there I'm getting a full 12 volts to my meeter and light. I was beginning to think the alt was bad but I've checked 3 and I am getting 12 volts from all 3 alternators. I haven't quite ever checked amps with this meter. How exly should I do it? Hooking up the negative and test between the battery positive and the cable to the car? That other red wire was for grounding yet the 3rd alternator pay no mind to it when I took this pic the alt power wire was off also. Picture was solely to see if I was doing the amp reading correctly
575645
 

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2005 STS 4.6
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6 Posts
Discussion Starter #6
575646

That's without the alt hooked up i couldn't video it but it jumped from 2 to 12 to 44 amps
 
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