Dead Short - Help?!?!?!?!
Thread Starter
Instructor
Joined: Feb 2003
Posts: 154
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From: Bethalto Illinois
Dead Short - Help?!?!?!?!
My 86 coupe was killng the battery from a full charge every two or three days. Well, the battery checked out ok. Autozone and NTB both put a load on the battery and it held up well.
So, I installed the battery, hooked up the negative post to the cable, and put a 12 volt bulb in series with the positive terminal.
The bulb lit bright as day, with nothing turned on - dead short. I pulled the fuses one at a time, hoping for the bulb to go out....damn!!!!
So now all the fuses are out, the bulb is still on, I disconnedted the alternator, and the buld is still on....
So, I guess the problem is in the starter or the solenoid, or the ignition switch or??????????????????????????
Any ideas on what to look for now, before I completely disasemble the entire car??? thanks :confused: :confused: :confused:
So, I installed the battery, hooked up the negative post to the cable, and put a 12 volt bulb in series with the positive terminal.
The bulb lit bright as day, with nothing turned on - dead short. I pulled the fuses one at a time, hoping for the bulb to go out....damn!!!!
So now all the fuses are out, the bulb is still on, I disconnedted the alternator, and the buld is still on....
So, I guess the problem is in the starter or the solenoid, or the ignition switch or??????????????????????????
Any ideas on what to look for now, before I completely disasemble the entire car??? thanks :confused: :confused: :confused:
Racer
Joined: Jan 2003
Posts: 321
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From: Birmingham AL
Re: Dead Short - Help?!?!?!?! (zog)
I'd put an ammeter between the battery post and battery cable to check current draw. Even though all fuses are out, there are several fusible links, etc. that could still be drawing current. Starter & alternator are also possibilities.
Keep us advised.
Do you have a wiring diagram ??? If not I may be able to help you out there.
Jim
Keep us advised.
Do you have a wiring diagram ??? If not I may be able to help you out there.
Jim
Team Owner
Joined: Mar 2001
Posts: 54,124
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From: Cincinnati, Oh USA
Re: Dead Short - Help?!?!?!?! (zog)
Remove the nut on the jump start bolt behind the battery and remove the 8 fusible links one at a time . Also, there are a number of circuit breakers that aren't removeable (unpluggable) and you will need to measure the current into all of these circuits. This is one time that a clamp on DC ammeter is extremely valuable. Cheapest one I know of is from Sears. Check the underhood lights, vanity mirror lights, courtesy lights. Do you have an aftermarket alarm or audio equipment? Try disconnecting them.
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Joined: Oct 2001
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From: Canton GA
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Re: Dead Short - Help?!?!?!?! (zog)
I'm with Jim on this, get an ammeter on it. Depending on the wattage of the bulb, it could be "bright as day" with as little as .5 amp draw which is only a little above what I'd consider normal. If you had a dead short somewhere, there would be a ton of smoke as your battery cables burned up.
Seeing how our cars are ALL electronic and all electronics have a parasitic current draw even when "off" (unless totally disconnected from a power supply), there will always be a drain on the battery. I had a head unit on the test bench and even when it was off, there was still a .1 amp draw to keep the presets.
Seeing how our cars are ALL electronic and all electronics have a parasitic current draw even when "off" (unless totally disconnected from a power supply), there will always be a drain on the battery. I had a head unit on the test bench and even when it was off, there was still a .1 amp draw to keep the presets.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Dead Short - Help?!?!?!?! (ShawnZR-1)
The leakage current in my 87 is 28 ma. 1/2 amp is WAY too much current and will discharge a car battery in 3 days. I would start looking for leakage current if it measured above 50 ma.
Thread Starter
Instructor
Joined: Feb 2003
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From: Bethalto Illinois
I think I found the problem (I hope)
After testing and checking everything I could think of, I traced the problem to the interior of the car. As a fluke, I pulled the seats and checked the power motor and seat inflator motor (for back rest). A friend of mine complained that his 85 Vette had troubles there.
Would you believe it??? The motor that pumps up the seat bags on the passanger side was so hot I could not touch it!!!! I unplugged all the stuff underboth seats and away we go...I HOPE.
Won't know for sure until the car sets a few days.....thanks for all of your posts. they gave me something to look for and saved a lot of aggrevation..... :party:
Would you believe it??? The motor that pumps up the seat bags on the passanger side was so hot I could not touch it!!!! I unplugged all the stuff underboth seats and away we go...I HOPE.
Won't know for sure until the car sets a few days.....thanks for all of your posts. they gave me something to look for and saved a lot of aggrevation..... :party:
