electrical problem
Thread Starter
Safety Car
Joined: Nov 2001
Posts: 3,632
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electrical problem
what is the best way to go about diagnosing the source of a power draw that leaves a battery dead overnight ? the alternator on my 86 l-98 still cranks between 13-14.5 amps , and the battery is new .
Safety Car
Joined: Jul 2001
Posts: 4,178
Likes: 2
From: Windermere FL
Re: electrical problem (markmaz)
It still may be the battery. If its new, I would be even more inclined to think it was. I have put in many new batteries that had cracked cells in them. If it dies overnight, try unplugging the battery after its charged and wait until the next day to see if it will work. Also, if it isn't the battery, its probably a bad interior light switch leaving a light on. Check your switches for your lights. Check door, glove boxes, hood, etc. This is the best place to start. If you have a meter you can unplug the hood lights and check the draw with the car off to see if you are drawing any power. Last, if you have installed anything aftermarket electronically, radar detector, alarm, sterio, lights, etc. check the power connections. If this doesn't do it, shoot it and put it out of its missery.
Thread Starter
Safety Car
Joined: Nov 2001
Posts: 3,632
Likes: 0
Re: electrical problem (92TripleBlack)
i'm still laughing about the idea of shooting it ... ...(it has crossed my mind) . it is not the interior lights . that was my first idea . i would have gotten rid of the new battery , but the a-holes at the parts store are giving me trouble.they want me to remove it so they can charge it first ... i have a viper alarm which is going this weekend . thanks a lot . m.
Drifting
Joined: Mar 1999
Posts: 1,931
Likes: 1
From: Norcross GA
Re: electrical problem (markmaz)
W/ the meter on the battery(current mode),... pull the fuses one at a time. It should be obvious which one is doing it. After that you will need a schematic to narrow your search further.
And of course, you do know that w/ the door open, (while pulling fuses) you will have a door light draw,..... so I won't mention that. :crazy:
And of course, you do know that w/ the door open, (while pulling fuses) you will have a door light draw,..... so I won't mention that. :crazy:
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: electrical problem (markmaz)
Yes, the current will drop dramatically when you remove the fuse in the circuit that is drawing current. You can remove the courtesy lights and keep the passenger door open so you can remove fuses one at a time. You should not have more than about 50 ma leakage current with everything off. I measured my 87 recently and after the courtesy lights timed out, I measured 26 ma. out of the battery. You might have a leaky diode in the alternator, so you can remove the large red wire on the alternator too. Be careful, there is 12 v on the wire , so if you hit ground with your wrench, you will blow the fusible link on the alternator wire. My money is on the aftermarket alarm!!! :D
Racer
Joined: May 2001
Posts: 378
Likes: 0
From: Dunmore, Pennsylvania
Re: electrical problem (markmaz)
There is a junction block behind the battery (called a jump start block, I think) which has about 10 wires connected to it.
You can take them all off and put them back one a time and check the leakage current, you might find your problem there.
Also check you battery cables for corrosion inside the plastic covers, sometimes you can't see it.
Good luck.
You can take them all off and put them back one a time and check the leakage current, you might find your problem there.
Also check you battery cables for corrosion inside the plastic covers, sometimes you can't see it.
Good luck.
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Instructor
Joined: Jun 2002
Posts: 177
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From: Escondido CA
Re: electrical problem (markmaz)
I have handled many prbs on cars other than vettes for excessive parasitic draw. Most common cause -a light staying on-second -alternator (have seen em charge fine and then suck it back out when off) third -aftermarket electronics ( alarms amps etc). Have also seen power antenna's never reaching the park position and causing it too. Do a general inspection for anything out of the ordinary and then the fuse by fuse method will isolate the troubled circuit. A handheld ammeter works good too if it is sensitive enough.
Thread Starter
Safety Car
Joined: Nov 2001
Posts: 3,632
Likes: 0
Re: electrical problem (ittlfly)
i finally got to the bottom of this . the battery had a bad cell . it would only push 6.5 amps . but the good news is that i took of an aftermarket alarm that kept setting vats off , and i learned a lot about electronics . thanks to everybody that helped me with this .
Safety Car
Joined: Jul 2001
Posts: 4,178
Likes: 2
From: Windermere FL
Re: electrical problem (markmaz)
Could still be a bad battery. Just because its new, doesn't mean its good. I went through 4 Die Hards once before I got a good one. Seems a whole pallet must have been dropped, cracking the majority of the battery cores. I'd have the new one tested and get a replacement that is the same make and model but from a different place. For example, if you got it from sears in town x, get the replacment in town Y.
Thread Starter
Safety Car
Joined: Nov 2001
Posts: 3,632
Likes: 0
Re: electrical problem (92TripleBlack)
if i am using the multimeter correctly , with the ignition on i crank at 13 amps , with the ignition off i am at 11-12 . it holds a charge for a few hours , but dies overnight .