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Author Topic:   Help with a short
Harrys'65
Gearhead

Posts: 338
From: Saint Paul, MN
Registered: Sep 99

posted 08-21-2001 09:42 PM     Click Here to See the Profile for Harrys'65   Click Here to Email Harrys'65     Edit/Delete Message   Reply w/Quote
I need some advise....I have been chasing an electrical problem and I am out of ideas.
Something is draining my battery, and I can't find it. Here is what I have done:
1 Bought a new battery(I was lazy, it was worth a shot)
2 charged the battery and left the + terminal off overnight it stayed charged
3 Charged the battery and left it hooked up..it drained overnight
4 Unhooked the + terminal and hooked up an amp meter in series with the battery. It measured 1.75DCA, so it is pulling current with everything shut off and everything off and shut
5 I pulled all the fuses under the dash one by one and measured the current at the battery, no change with any of them.
6 I measured current with the lights on 8amps

I am now stumped. bad voltage regulator, alternator, anything else???

Thanks for the help.

------------------
Harry Straub
'65 Mustang Coupe
http://www.harrystraub.com/resto.html

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franklin
Gearhead

Posts: 128
From: VA
Registered: Nov 2000

posted 08-22-2001 12:27 AM     Click Here to See the Profile for franklin     Edit/Delete Message   Reply w/Quote
Put your amp guage back on, and start this time at the starter solenoid. There should be some smaller wires attached to the large terminal on the solenoid that goes to the battery. This is the point where the whole car's electrical system is fed, and also where the alternator output is joined in too. Pull these smaller wires off and see if the it leads you back in the car interior or over to the alternator.

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SteveLaRiviere
Administrator

Posts: 24286
From: Saco, Maine Toys: '70 Mustang Mach 1 - '72 Mustang Sprint - '94 F-150
Registered: May 99

posted 08-22-2001 06:27 PM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
If you pull your fuses one by one, you may be able to find the circuit the short is on by noting which fuse eliminates the draw.

------------------
'70 Mustang Mach 1 M code 351C 4V/FMX/3.25 open
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Lok
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
'97 Probe GTS 2.5L DOHC
Ford. The closer you look, the better WE look!

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Harrys'65
Gearhead

Posts: 338
From: Saint Paul, MN
Registered: Sep 99

posted 08-25-2001 02:55 PM     Click Here to See the Profile for Harrys'65   Click Here to Email Harrys'65     Edit/Delete Message   Reply w/Quote
I have the short narrowed down thanks to Franklin.....when I remove the connector that has the Alternator/headlights on it from the solenoid, the short goes away.
How can I test me Alternator for a short? Any suggestions?

Thanks for the help.
Harry

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franklin
Gearhead

Posts: 128
From: VA
Registered: Nov 2000

posted 08-25-2001 04:44 PM     Click Here to See the Profile for franklin     Edit/Delete Message   Reply w/Quote
There is a wire that goes to the regulator from the ignition switch circuit. This tells the regulator to put the alternator "online" when the key is turned on and "offline" when the key is turned off to keep the alt from draining the battery. So it could be the regulator, but alot of guys like to change the alternator and regulator as a set. I would try taking the alternator down to the parts store and get them to test it to see if it is good (they do this for free I think). If you are not strapped for money, and the alternator is pretty old, I would get a new one (or get it rebuilt by a local auto elec shop if you want to stay original) and a new regulator.

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Harrys'65
Gearhead

Posts: 338
From: Saint Paul, MN
Registered: Sep 99

posted 08-25-2001 08:43 PM     Click Here to See the Profile for Harrys'65   Click Here to Email Harrys'65     Edit/Delete Message   Reply w/Quote
Thanks Franklin, I actually just got back from NAPA with a new alternator. The old one tested good, but I just couldn't trust it so I spent the $34 for a new one. I just installed it, and I still have the short. (I hate it when that happens).
So, I guess tomorrow it is a new voltage regulator. The wiring harness is a little monkeyed up, but I have gone over it and it seems fine.
Thanks for the help.
Harry

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Harrys'65
Gearhead

Posts: 338
From: Saint Paul, MN
Registered: Sep 99

posted 08-26-2001 04:16 PM     Click Here to See the Profile for Harrys'65   Click Here to Email Harrys'65     Edit/Delete Message   Reply w/Quote
HELP. First let me say that I hate electrical problems...give a brake, clutch or mechanical problem and I will get it done.

I got a new regulator today and the problem is WORSE. Can ANYONE give a clue as to why with the ignition OFF the there is a current pull that goes from 4 amps to 0 amps every 10 seconds? It will pull 4 amps for 2 seconds then 0 for 10 seconds. Anyone? I tried both regulators(new and old) and both are doing it. I am stumped and frustrated and my wife says "grumpy".

Thanks.
Harry

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sigtauenus
Gearhead

Posts: 1602
From: Beaufort, SC
Registered: Jun 2000

posted 08-26-2001 07:12 PM     Click Here to See the Profile for sigtauenus   Click Here to Email sigtauenus     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Harrys'65:
HELP. First let me say that I hate electrical problems...

I am stumped and frustrated and my wife says "grumpy".

Thanks.
Harry



Harry, here's the only suggestion I can make. Unhook the battery so it doesn't drain again. Go inside and watch some football, have a beer, relax a little, and go back to work on the car tomorrow when you are fresh and unwound. I know from experience that nothing good happens to my car when I'm frustrated.

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franklin
Gearhead

Posts: 128
From: VA
Registered: Nov 2000

posted 08-26-2001 09:30 PM     Click Here to See the Profile for franklin     Edit/Delete Message   Reply w/Quote
First, take sigtauenus' advice. Then I would verify again which wire is the culprit. Follow the wire to see where it goes. If it is the alternator, you must have a wiring problem since everything is new. I can't seem to find my 65 wiring diagram, but I have a generic reg/alt diagram that should work. Do you have a idiot light for the alt in the dash? If so, when you turn the key on, you should have 12v on terminal "I" of the reg. At no other time should you have voltage on this terminal. "F" on the reg should go to the field term of the alt. "S" should go to the stator term on the alt. "A" should be attached somewhere that leads to the battery.

[This message has been edited by franklin (edited 08-26-2001).]

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Harrys'65
Gearhead

Posts: 338
From: Saint Paul, MN
Registered: Sep 99

posted 08-26-2001 10:02 PM     Click Here to See the Profile for Harrys'65   Click Here to Email Harrys'65     Edit/Delete Message   Reply w/Quote
Thanks Guys.
I have taken some of the advise and just finished a nice dinner and playing cards with my daughter.
I also just read the manual(again). The best I can tell everything is OK now. There is a current draw, but it is variable and decreasing. According to the manual the alternator does take a variable charge with the engine off until it is charged. I will see in the AM. The variable current is 0-2amps now and decreasing.
I will keep you posted. If not, i will go back to the drawing board and start tracing wires again.
Thanks
Harry

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