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Old 04-21-2019, 10:00 PM   #1
James G
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Default Oh boy - an electrical problem.

Put in a new battery after a defective battery minder cooked the old one over the winter. Replaced the battery thinking that would fix the problem. The starter will turn but none of the electrical items function (lights, horn). Found the fuse on the distributor blown and replaced it. That fuse blows the second it is replaced and I turn on the power.

I am completely baffled. Any suggestions would be appreciated.
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Old 04-21-2019, 10:07 PM   #2
J Franklin
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Default Re: Oh boy - an electrical problem.

Disconnect and isolate your shorted wire. The ability to use a volt/ohm meter is most important in locating electrical problems.
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Old 04-21-2019, 10:15 PM   #3
Dick Steinkamp
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Default Re: Oh boy - an electrical problem.

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Found the fuse on the distributor blown .
???
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Old 04-22-2019, 01:15 AM   #4
Mike V. Florida
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Default Re: Oh boy - an electrical problem.

You need a wiring diagram and a meter or at least a test light. We can keep guessing as to where the problem could until each and every component is mentioned. Place a light bulb across the fuse holder in place of the fuse so when the short is found the light will go out.





To start the trouble shooting I would open the headlights and disconnect the wires as shorts in the buckets are common. Good luck!!
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Old 04-22-2019, 09:36 AM   #5
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Default Re: Oh boy - an electrical problem.

Quote:
Originally Posted by James G View Post
Put in a new battery after a defective battery minder cooked the old one over the winter. Replaced the battery thinking that would fix the problem. The starter will turn but none of the electrical items function (lights, horn). Found the fuse on the distributor blown and replaced it. That fuse blows the second it is replaced and I turn on the power.

I am completely baffled. Any suggestions would be appreciated.
Troubleshooting electrical problems on vehicle wiring requires at the minimum, for me, a functional ohm meter set on the lowest range. And with the fuse blown and out of the circuit, hook the ohm meter on the lowest range to ground and the fuse post (not connected to the battery), and in fact to protect the ohm meter disconnect the battery! If there is a short in your wiring, the ohm meter should read 0 ohms or close to it. The next step is start disconnecting wires or looking for open wires shorted to ground. This can get complex or something cosmetic or physical will stand out. Sadly, this kind of effort takes a bit of electrical ability and knowledge. Get help if needed.
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Old 04-22-2019, 10:35 AM   #6
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Default Re: Oh boy - an electrical problem.

I think the short killed the battery tender and the battery at the same time. As Mike V suggests, use a test light of some kind across the fuse terminals. Start by disconnecting the wires at the cutout and check the test light. Divide and conquer. Most common problem is stuck cutout contacts, but could be anywhere in the main line, including horn, lighting switch and ammeter.
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Old 04-22-2019, 10:50 AM   #7
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Default Re: Oh boy - an electrical problem.

6 volt or 12 volt, generator or alternator, negative or positive ground????
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Old 04-22-2019, 10:54 AM   #8
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Default Re: Oh boy - an electrical problem.

Quote:
Originally Posted by James G View Post
Put in a new battery after a defective battery minder cooked the old one over the winter. Replaced the battery thinking that would fix the problem. The starter will turn but none of the electrical items function (lights, horn). Found the fuse on the distributor blown and replaced it. That fuse blows the second it is replaced and I turn on the power.

I am completely baffled. Any suggestions would be appreciated.


Battery in backwards???
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Old 04-22-2019, 10:56 AM   #9
Dick Steinkamp
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Default Re: Oh boy - an electrical problem.

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6 volt or 12 volt, generator or alternator, negative or positive ground????
Bob
....and what is the "fuse on the distributor"? Most aftermarket fuses were on the starter and protected everything (except the starter itself). Are you just protecting the ignition circuit?

When you say "That fuse blows the second it is replaced and I turn on the power", do you mean when you turn on the ignition key or do you have a battery disconnect switch?
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Old 04-22-2019, 11:33 AM   #10
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Default Re: Oh boy - an electrical problem.

No fuses on the distributor that I'm aware of. If it still has the armored ignition cable then that is the only connection to the distributor. The coil connects to that with the other terminal to the buss. If there was a short on a hot wire somewhere then the battery would have drained and the tender would have tried to keep the battery charged through all that. That would likely fry the tender. Battery should be disconnected for long slumbers.
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Old 04-22-2019, 11:50 AM   #11
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Default Re: Oh boy - an electrical problem.

I agree, your baffled. Get the wire diagram and read all of the above helpful posts until it begins to make some sense. Get to know what open, closed and shorted really means. Take your time, learning this is more important than getting the car running again.
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Old 04-22-2019, 01:25 PM   #12
Dick Steinkamp
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Default Re: Oh boy - an electrical problem.

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If there was a short on a hot wire somewhere then the battery would have drained and the tender would have tried to keep the battery charged through all that. That would likely fry the tender. Battery should be disconnected for long slumbers.
If there was a short, wouldn't the fuse blow disconnecting the battery and the charger from the short?
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Old 04-22-2019, 05:44 PM   #13
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Default Re: Oh boy - an electrical problem.

Model A vehicles didn't originally come with any sort of fuse. Cars burned up back in the day until manufacturers started installing a fuse block. Owners and repair shops started installing a fuse block at the buss connection to the starter just to prevent this. The problem is that a person has to go through a bit more work to track down a short if the fuse blows. Otherwise a person has to have a fist full of fuses if you use the fuse to find the short. Each separate circuit has to be isolated and an ohm test meter or multi-meter used to check each for short to ground.

The Model A is the best vehicle to learn automotive electric troubleshooting on since it is about as simple a system as there is. The lighting system is the most complex part of it and there really aren't many light bulbs on a standard type car. The switch is down low on the steering column where it is vulnerable to weather and vibration. Loose wiring adds resistance to a circuit and resistance turns to heat in the system. The terminal box below the coil on the firewall has to be checked now and then for loose connections. The late type plastic reproductions of these terminal boxes will melt if they get hot from loose wiring terminals. The old original bakelite ones are the best.

If a person forgets to turn off the ignition for one reason or another, and the breaker points happen to be closed, the coil will turn into an electromagnet and run the battery down. It usually burns up the coil too.

As far as whether the fuse will blow or not depends on whether it is a short to ground or whether some electrical component is just energized like the coil I just mentioned or even a bad brake light switch. Neither of these would burn the fuse but it could ruin the battery over a short period of time and may do other damage depending on the condition of the system.

Last edited by rotorwrench; 04-22-2019 at 05:54 PM.
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Old 04-26-2019, 09:09 AM   #14
Bob Wright
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Default Re: Oh boy - an electrical problem.

Maybe these will help
Bob
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Old 04-27-2019, 08:54 AM   #15
Tom Wesenberg
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Default Re: Oh boy - an electrical problem.

Some repro brake switches also have a short to ground, and this is when new.
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Old 04-27-2019, 09:30 AM   #16
30Ford
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Default Re: Oh boy - an electrical problem.

Disconnect the lights from the bottom of the steering colum ..then you just have power running from the battery to the points and to the dash lights see if you still have a problem ...check the amp meter too seen them ground out
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