MTFCA Forum

Hey fellers, drove my car around today and all was well. Battery was charging and no issues. Came home and tightened up my 4 bolts holding my switch and ammeter and hooked up my battery and saw a little smoke starting to come from my ammeter- it was hot?

Here is my wiring- anything look out of place? A little puzzling to me.

Thanks,
Jim

https://youtu.be/n85WuQachEQ?si=vkoYmr_DkAmpn6hQ . ....... Same problem with model a reproduction ammeters... Just follow the instructions and Make the connections better.

If the tag says GEN then possibly Looks like you have a wire tagged GEN to the MAG screw position. This by itself would just effect the switch position BUT likely other wires arr crossed.
There are two screws for the BAT position with a jumper across them so it doesn't matter which is used for that connection
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Another possibility if all wiring is correct, over tightening the nuts on the ammeter could brake loose the internal connections --
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Same wiring rectangle or oval plate

Till you're ready to fix your problem, I would suggest disconnecting the positive terminal on your battery just for safety's sake

Moxie26 wrote: ↑

Sun Dec 01, 2024 5:17 pm

Till you're ready to fix your problem, I would suggest disconnecting the positive terminal on your battery just for safety's sake

ONLY if it is a POSITIVE ground. ALWAYS DISCONNECT THE GROUND AT THE BATTERY. The GROUND can be Positive OR Negative. Look to see which cable goes to the frame. That's the ground.

Removing the ground is safer because IF your tool (wrench or whatever you are using) happens to touch part of the frame, there will be no sparks and no damage.

Yep, the negative is disconnected at battery.

The same happens if the positive terminal is disconnected from the battery ........ Would also help if you installed a 20 amp fuse at the starter switch terminal that the yellow #12 gauge wire connects.

A similar smoking situation happen to me on a tour a couple of years ago. Lots of smoke! It turned out that a "hot wire" had been rubbing on the bottom edge of the dash for years and the sharp edge of the dash rubbed the insulation off of the wire, creating a short. There was a fuse on the line but the fuse never blew. The problem was not hard to find.

Fozz71 wrote: ↑

Sun Dec 01, 2024 4:39 pm

Hey fellers, drove my car around today and all was well. Battery was charging and no issues. Came home and tightened up my 4 bolts holding my switch and ammeter and hooked up my battery and saw a little smoke starting to come from my ammeter- it was hot?

Here is my wiring- anything look out of place? A little puzzling to me.

Thanks,
Jim

I forgot to ask. Why are there 3 wires connected to the ammeter. The Green is okay, one should be to the battery on the opposite post, so what the other one on the post with the green wire?

That's what I was thinking, I'll have to check that 3rd wire out.

Fozz71 wrote: ↑

Mon Dec 02, 2024 8:22 am

That's what I was thinking, I'll have to check that 3rd wire out.

Here is a wiring diagram for cars with starters & generators. I also updated the other diagram to show where the Generator connection goes. Its also possible to connect it at the ammeter to where the yellow/black (your green) wire is. Check all the connections & what you noted in the tabs

I suspect that if you remove all wires except the green one from your ammeter, you will still see smoke.

I’m thinking the paper insulator inside the can is bad.

Yeah, hello comfortable, the paper so-called insulator is getting warm because of the loose connections inside the ammeter. If you follow that video that I posted, those loose connections can be corrected, at least tried to be corrected. If not, you'll have to get a better 20-0- 20 amp meter.,.......... Could it be that a previous owner put that green third wire on the ammeter as a source of power for auxiliary lighting or even a cigarette lighter, or even a charge port for some electronic equipment such as a Garmin or a cell phone?...... Where does the other end of that green wire end up?

Maybe this ammeter will do the trick?

https://www.ebay.com/itm/145715529890?_ ... R-yKgIrxZA

That's the same repro you have now !

Fozz71..... If you do get it, just use the video as a guide and with an analog meter, my choice, check the readings, you may have to proceed to solder the connections.

Thanks for all the help, I moved the extra wire from the ammeter back to the screw on the switch (where it seemed to be missing) and everything is good now. Yes, the new ammeters are kinda junky but I tightened all connections and will keep an eye on it. Thanks for all the help!

Use a different ammeter with an ammeter adapter.

This is one I did for a 12 Volt Alternator.
This is the tool.