Need Help in Identifying Location of Short

[shew01]

My 1931 Victoria is 6 volt positive ground, and I recently replaced my repro ignition switch and cable with a rebuilt one from Dick Crabtree.

The previous owner installed a power cutoff on the positive side of the battery, and I normally leave the car plugged into a battery minder (https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1). The previous owner gave me the battery minder when I purchased the car; so, this unit has been successful for a number of years.

If leave the power cutoff turned "off," the battery remains at 6 volts, as it should. If I leave the power cutoff turned "on," the battery will drop to about 1.5 volts in less than 24 hours, even with the battery minder plugged in.

I presume the issue is with the rebuilt ignition switch or the wiring in the junction box that I disturbed to replace it. I'm not sure where to look or how to test. I do have a multimeter, but I need direction for how to proceed.

Any help is appreciated.

[Sunnybrook Farm]

Do you have the armored cable that screws into the distributor, looks like a big spring? A couple things to check if that is what you have, first and easy to check is where it screws into the distributor, it could be screwed in too far and may push the lower plate against the body, it just needs to be tight enough to make good contact with the spring loaded plunger. Also there is a regular insulated wire that runs up that spring like case and that can rub and make contact. The switch itself could have a break in the internal insulation that is leaking. I had an old original switch that actually got warm so I just got one at NAPA and use that since I don't plan on showing the car anymore. If you have a test meter you can start testing all these different places or just switch back to your old switch to see if that is the problem. I had a cable give me problems on the old rusty car so I just ran a wire directly from the switch to the lower plate and connected with a screw, looks bad but works with out that antithieft armored cable with the spring and copper plunger. ( you don't want to do that, haha)

[shew01]

Originally Posted by Sunnybrook Farm

Do you have the armored cable that screws into the distributor, looks like a big spring?

Yes, it is an original popup ignition switch, rebuilt by Dick Crabtree.

Originally Posted by Sunnybrook Farm

first and easy to check is where it screws into the distributor, it could be screwed in too far and may push the lower plate against the body, it just needs to be tight enough to make good contact with the spring loaded plunger.

How can you determine if it is screwed in too far? I made an educated guess and screwed it in about 3 turns. It will screw 7 turns before it gets "tight."

Originally Posted by Sunnybrook Farm

Also there is a regular insulated wire that runs up that spring like case and that can rub and make contact.

That wire appears to be new.

Originally Posted by Sunnybrook Farm

The switch itself could have a break in the internal insulation that is leaking. I had an old original switch that actually got warm so I just got one at NAPA and use that since I don't plan on showing the car anymore.

The switch does not appear to get warm. Just the coil gets warm.

Originally Posted by Sunnybrook Farm

just switch back to your old switch to see if that is the problem

I thought about that, but I was hoping to find the issue without the headache of swapping out the cable twice more. Ultimately, I may not have much of a choice.

[Jim/GA]

Do you have this book:

https://www.mafca.com/cart/index.php?productID=168

Look at the wiring diagrams and make sure you have the wires hooked up correctly.

You may have to open things up and take some pictures of how you have it all wired up, then post them here, for someone to help you spot the error.

[shew01]

Originally Posted by Jim/GA

Do you have this book:

https://www.mafca.com/cart/index.php?productID=168

Look at the wiring diagrams and make sure you have the wires hooked up correctly.

You may have to open things up and take some pictures of how you have it all wired up, then post them here, for someone to help you spot the error.

Yes, I have that book. I took copious pictures before I took anything apart. I labeled the wires before removing them from the junction box terminals to check out Tom Endy's information about the screws that tend to short on the firewall. I think the wires are hooked up to the proper terminals.

[wmws]

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Turn your disconnect switch to on. Disconnect wires to head lights tail lights horn etc. one at a time. Then hook you multimeter in the line to see if it is drawing current. Or even while your disconnecting wires if you see a little spark that is the bad one.

[Ed in Maine]

Last month I removed the instrument panel on my 31 Victoria and managed to create a short while putting in back in. In my case, the metallic covering on the dash lite wire had gotten up against one of the terminals of the ampere meter. I wrapped it with electrical tape in that area of the ampere meter terminal to solve the problem. Good luck, Ed

[shew01]

Originally Posted by Ed in Maine

Last month I removed the instrument panel on my 31 Victoria and managed to create a short while putting in back in. In my case, the metallic covering on the dash lite wire had gotten up against one of the terminals of the ampere meter. I wrapped it with electrical tape in that area of the ampere meter terminal to solve the problem. Good luck, Ed

Prior to installation, I wrapped the ignition switch with tape to prevent any potential shorts. The ammeter does not seem to be grounding to the firewall. At the moment, I have the 4 instrument panel screws removed, and the panel is ajar from the dash. So, I don't think the ammeter is the issue (at least for now).

[Gary WA]

Originally Posted by shew01

My 1931 Victoria is 6 volt positive ground, and I recently replaced my repro ignition switch and cable with a rebuilt one from Dick Crabtree.

The previous owner installed a power cutoff on the positive side of the battery, and I normally leave the car plugged into a battery minder (https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1). The previous owner gave me the battery minder when I purchased the car; so, this unit has been successful for a number of years.

If leave the power cutoff turned "off," the battery remains at 6 volts, as it should. If I leave the power cutoff turned "on," the battery will drop to about 1.5 volts in less than 24 hours, even with the battery minder plugged in.

I presume the issue is with the rebuilt ignition switch or the wiring in the junction box that I disturbed to replace it. I'm not sure where to look or how to test. I do have a multimeter, but I need direction for how to proceed.

Any help is appreciated.

How old is Battery?Re-look at what you did to replace the items?

[shew01]

Originally Posted by Gary WA

How old is Battery?Re-look at what you did to replace the items?

I don't know the age of the battery, but it charges back up to 6 volts if I turn "off" the power cutoff.

I'm still looking at what I did to replace the items. Nothing seems wrong yet.

[jrelliott]

Take a small 6V bulb and attach alligator clips on insulated wires about 6" long for each wire to the bulb on the end where it makes contact in a socket and the sides with solder. Would suggest you place heat shrink tubing around the connections on the bulb Attach the alligator clips across the terminals of the cutoff switch when in the "OFF" position. You will need the battery to be charged up. If there is a current draw, then the bulb will light up. Start disconnecting the wires to headlight, horn, tail lights etc. until you find the short.

[Patrick L.]

So you now have a draw when the master switch is on but the key switch is off ?

Just take our volt meter or test light, remove a battery lead that is easiest to get at. Connect the test light or meter between what you just disconnected. [ the ground battery terminal and its cable are the best, but any will do] The light will come on or the meter will show the draw. Disconnect 'stuff' until the light goes our or the meter shows no draw and thats your problem.

[Big hammer]

If you would have a short you would have a hot spot or smoke. If your having a draw down I would check the generator cut out to see if it is sticking closed. Remove the fan belt and see if the generator motors.

[Tom Endy]

See attached article.

Tom Endy

[shew01]

Originally Posted by Big hammer

If you would have a short you would have a hot spot or smoke. If your having a draw down I would check the generator cut out to see if it is sticking closed. Remove the fan belt and see if the generator motors.

I should have mentioned that I have a 6 volt positive ground alternator. Would an alternator have a similar potential issue?

[Tom Endy]

Originally Posted by shew01

I should have mentioned that I have a 6 volt positive ground alternator. Would an alternator have a similar potential issue?

Alternators have a series of diodes in the output. A diode has a small amount of reverse current, it is not like a switch.

The same thing applies to a cutout that has been modified with a diode. If you leave the car sit for a month or so you will have a dead battery if power is applied.

I have a 6-volt positive ground alternator on my Victoria. A few years ago a diode failed and it kept running my battery down, even though it worked fine and put out power. I had to replace it.

The problem you are having is abnormal for a properly working alternator. It may be you have a failed diode in it. Disconnect the alternator and see if it resolves the problem.

Tom Endy

[shew01]

Originally Posted by Tom Endy

Disconnect the alternator and see if it resolves the problem.

Tom Endy

I tested again with the alternator disconnected, but the results are the same with the ignition key “off” (“in”) and the red wire screwed to the side of the ignition switch.






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[Jacksonlll]

If you are drawing that much current, then something is getting warm or even hot. Look for it. Usual suspects are: lights, including the brake light, generator trying to motor, short down stream of coil, Some little wire getting very hot. Good luck.

[shew01]

Originally Posted by Jacksonlll

If you are drawing that much current, then something is getting warm or even hot. Look for it. Usual suspects are: lights, including the brake light, generator trying to motor, short down stream of coil, Some little wire getting very hot. Good luck.

I started looking for something warm, and it turns out the coil is warm.

Here is something else odd. With the cutoff power “on,” and the ignition key “on,” I get 6 volts to the moving point arm when the points are open, as expected. However, under the same scenario, but with the ignition key “off,” I get still get .3 volts on the moving point arm.


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[The Master Cylinder]

Originally Posted by shew01

With the cutoff power “on,” and the ignition key “on,” I get 6 volts to the moving point arm when the points are open, as expected. However, under the same scenario, but with the ignition key “off,” I get still get .3 volts on the moving point arm.

Sounds to me as if you have something connected incorrectly or your switch is BO and leaking thru. With switch off there should be zero voltage at the points, if you car is wired correctly.

Do you have any accessories wired into the ignition switch?