Author Topic: Need help with finding a short in the ignition/charging system  (Read 1540 times)

Offline challengermaniac

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Need help with finding a short in the ignition/charging system
« on: January 01, 2009 - 07:29:30 PM »
Hi there,

Would greatly appreciate it, if someone could walk me through each of the electrical checks I need to run through (key off, key on but motor not running & motor running) in order to check my ignition and charging systems.  I have a short that is draining the battery AND when I turn the key, the motor doesn't even crank over.  I suspect there is a problem at the ignition key in the steering column, but I have never gotten into one, so I don't know where to start.  Thanks for your help.

Charlie 70 Challenger
69 Camaro RS
Charlie
70 Challenger 340/4 Purple
70 Challenger T/A Red
Edmonds, WA




Offline FY1Cuda

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Re: Need help with finding a short in the ignition/charging system
« Reply #1 on: January 03, 2009 - 05:43:56 PM »
If you have a short anywhere, it's going to drain the battery so the car won't turn over, so it doesn't necessarily mean the issue is in the ignition.  We just had problems on a Challenger draining the battery, and it turned out that the turn signal switch was shorting.  I presume you had the battery checked and it holds a charge (and doesn't have an internal short).
The problem is most likely in the dash area so you can try a few things after you recharge your battery.
Suggestions:
Look under the dash for burnt or melted wires. For example, one of the pink wires that go to the brake light switch above the pedal is live, so if it's hitting the pedal, you could have a drain.
The thick red and black wires that go to the ammeter on the dash have little plastic bushings that keep the posts from touching the instrument cluster housing. If either of those is loose, you can easily have a short.
Disconnect the white nylon 8-wire turnsignal switch connector (white wire on one end, black on the other) above the brake pedal and see if the battery holds a charge.
You can pull fuses, one at a time, and see if the car holds the charge overnight.
This is basically trial and error, so have patience.  If you're going to be spending a lot of time under the dash, do yourself a favor and take the seat out.  Loosening those 4 nuts will have your back thanking you later.
Good luck

Offline Chryco Psycho

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Re: Need help with finding a short in the ignition/charging system
« Reply #2 on: January 03, 2009 - 09:54:04 PM »
I would start disconnecting circuits until the draw stops , at least it will narrow down where to look

Challenger - You`ll wish You Hadn`t

Offline 426HEMI

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Re: Need help with finding a short in the ignition/charging system
« Reply #3 on: January 03, 2009 - 09:58:46 PM »
I would agree with that.  How much of a draw do you have?  On this car there is several ways to check that which are safe.  Taking a circuit out by removing fuses helps to eleminate the drain then you can trace down the drain when you find the circuit it is in.  What have you checked or looked at so for?  Will be glad to help anyway I can to find the problem.
Got a pretty good start on my M46 optioned Barracuda restoration but now it is on hold till I can gather more funds.  Still need a few parts for it.  SIU Graduate 75 AAS Automotive Tech, 94 BS Advanced Tech Studies, 1997 MSED Workforce Education and Development

1970 M46 Barracuda
1998 Dodge Darango

Gordon

Offline basement

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Re: Need help with finding a short in the ignition/charging system
« Reply #4 on: January 09, 2009 - 01:21:10 PM »
I agree with FY1Cuda, try pulling the fuses one at a time. If you have an Ammeter you could put that in series with the positive side of the battery and try removing the fuses one at a time until the current drops to zero. This might help point you in the right direction. Good luck

Offline 72 cuda

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Re: Need help with finding a short in the ignition/charging system
« Reply #5 on: January 15, 2009 - 07:28:17 AM »
Quick question,for a redundant system.
Take a test light, bridge from the negitive pole on the battery and the terminal (disconnected).
If it lights you have an open circut (drain on the battery) pull the fuses one by one,until the light goes out.
And thats the culprit.
It won't help  stop car thieves but it will fix the battery drain .Possibly something as simple as a glove box light stuck on you can't see.??
PS you probably already knew this. for what its worth.
Mark