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Discussion Starter #1
I developed a draw on my 67 Vert battery so I get under the hood to try to find it. I don't know much about wiring.

After re-reviewing the wiring diagrams and running our to the car, the problem appears to be the black w/yellow wires.
Ok, it appears that on this diagram: Ignition/Charging Wiring Diagram- the Wires are 37B and 37 and 37A after they spilt from at the Starter Relay.

37B and 37A are completely striped of insulation.

Clearly, I need to replace them.

Can someone please tell me which wiring harness I need to buy.

Also, do you believe the problem is not with 37, A & B, that this just might be a symptom?


T.I.A.

And FYI here are all of the 67 Wiring Diagrams
 

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Hey you might want to disconnect the battery if you havent already done it sounds to me like you have a short that has caused all the insulation on the wires to be melted off the short could be what is draining you battery i dont know enough about the wiring to tell you what the wires go to but it would better be safe than sorry. sorry that i couldnt be of more help but im sure that someone on here will. Jeff
 

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You stand a great chance of burning that cool car to the ground......get a local expert.
 

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Discussion Starter #4
I immediately pulled the battery when I saw all that exposed wire. :)
 

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37A and B are the main power wires from the battery side of the starter solenoid switch to the fuse box and ammeters. If the insulation is burned off, then yes, you have a very serious short somewhere, most likely under the dash or at the ammeter. I'm surprised the car didn't burned to the ground. At a minimum, you'll need to replace the underhood wiring harness.

When you get this far, post or PM me for explicit details for isolating a major short like this. If you don't have one already, get a quality digital volt-ohm meter that can also measure up to 10 amps DC or more.
 

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Discussion Starter #6
Thank you. I'll order the wiring harness.

I'll be in touch once I get deeper into this, I think I need a beer right now. :(
 

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From the wire route , Id suspect either the ignition switch , the alternator , or a general short of the wire inbetween .
Your gonna have to get into the dash to see if the wiring under there got melted too . Normally when a short happens , the wire will melt between the short and the 12v supply source . If it's melted under the dash , you got big issues methinks .
 

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First of all, How did you determine you had a draw on the battery? How much of a drain? As for the wires, unless they touch ground (electrical ground not the dirt.) they won't short circuit. If it did you would see maximum smoke and a large section of insulation would melt or burn. Just use electrical tape to wrap them individually until you can replace that loom. The insulation may have dried out and broken off due to the conditions under the hood. The Black w/ yellow and Yellow wires are 12V obtained from the starter solenoid. B & Y goes to the fuse block and power is distributed from there. Yellow appears to go to the Alt. If you have a small draw it may be a courtesy light, radio that has the volume down low, a fan motor on low or something like that. Just verify everything is off and disconnect one item at a time until the draw disappears. Trust me, If you had a SHORT you would know real quick. I would need more info and probably a photo to tell more.
 

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Discussion Starter #9
Ok, car was doing fine, but the inner fender at the battery was eaten with rust, so I replaced it.

After I replaced it I had the draw on the battery - the battery was dead, I charged it thinking it was just old and the car had been sitting for about a month, it took a charge but the next day, dead again - so I started taking the electrical tape/wrap that bundles the wires off to test the wires for a short (in the area where I had been welding and cutting) when I saw the one wire was bare, from there I removed all of the electrical wrap and here I am.

To be honest I don't know when this short occurred or if it was present before I started messing with the inner fender (prior to then I was able to drive the car from Ft Worth to Austin, then a little bit around town before I started the resto).

But that wire is bare.
 

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ok now with your last post it sounds like maybe a previous owner had the short and instead of fixing it right he opted for the ole black tape will do trick and because your battery started to drain down you started investigating and found the previous short thats why there wasnt any smoke or anything. It could be that the bare wire may have nothing to do with your battery being drained
 

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Red:

Is it possible that the insulation damage to those wires was caused by your recent welding? If so, further troubleshooting would, in all liklihood, be unnecessary.

As for replacing the harness, there are three underhood harnesses for a '67. IIRC the main harness, often called the headlight harness, is the one that has wires 37, 37A & 37B. Like the rest of the underhood harnesses, they are reproduced and available from most Mustang Parts vendors. I would suggest that you consider placing an inline fuse or circuit breaker close to the solenoid to protect the rest of your electrical system from further damage due to excessive electrical loads.
 

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Discussion Starter #13
Isrjf: I removed the battery and selenoid and just zip-tied everything else out of the way.

JeffT: I realy don't think the problem was do to the welding, because I was especially careful of the wires (but anything is possible). I love the idea of installing an inline fuse and will definately do so.

Might the problem be with the selenoid? I mean those are cheap and easy enought to replace.
 

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It is unlikely that it is a solenoid; it is basically just a switch. If it is on, all it does is provide power to the coil (or starter...you'd know if that was on!), and the coil just sitting there with the engine not running doesn't draw much current. At worst, the points would burn up, but that's no biggie. It might certainly be the source of your power draw, however. Easy to check: just remove the two small wires on the solenoid.
 

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My '67 had a similar problem, the previous owner had used foil to replace a fuse. I only noticed the melted insulation while I was looking to wire for fuel injection. I figured that there was no telling what kind of a gremlin was responsible for the blown fuse in the first place. I decided to re-wire the entire car and went with a Painless kit. It was expensive, but not as expensive as a car fire.
 
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