The Ford Barn

Hunterspeedandkustoms · 02-24-2019, 08:09 PM

Did a pretty basic conversion from 6v to 12v today.

New 12v battery, 12v alternator, 12v coil, 12v amp gauge, new 12v bulbs.

Got the car to fire up after doing the conversion, all seemed well.

Started changing the tail light bulbs, got the running lamps working successfully first, then started on the brake lights. During testing the brake lights (unsuccesfully) I lost power. Running lights don't work anymore, turning the key I have no power to attempt to start the car again.

Confused. Battery is showing 95% charge. Short circuit somewhere? But why suddenly? Only thing I can think to do is start over fresh on the battery connections to ensure I have a really solid ground and tight connections on the poles. Thoughts?

Ruth · 02-24-2019, 08:18 PM

Really stupid question on my part but I have to ask. Do you have a main fuse? To lose everything so fast the first thing I thought of.

Hunterspeedandkustoms · 02-24-2019, 09:51 PM

Not a stupid question at all. That's a helpful suggestion I hadn't thought about Ruth. I'm a recent owner of this coupe and I'm not 100% sure about the ins-and-outs of this electrical system. Best I can tell, there is no master fuse. The only fuse on it seems to be the one I installed a while back off the starter. While I had hoped to avoid it, sounds like I may just need to go through the wiring thoroughly.

Jim/GA · 02-24-2019, 10:24 PM

What year is this vehicle?

Did you change from original positive ground to negative ground when you changed to 12 volts?

The "master fuse" that Ruth asks about IS the one you installed on the starter a while back.

Hunterspeedandkustoms · 02-24-2019, 11:02 PM

Gotcha Jim. Yes changed from positive ground to negative ground. I eyeballed the fuse at the starter and it looks good. Tomorrow night will change it out or bypass it to rule that out as a factor.

Jim/GA · 02-24-2019, 11:11 PM

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Slow down, ace. Fuses blow for a reason. If you bypass it, you will end up with an electrical fire. You need to determine why the fuse blew.

I asked what year car this is because the 1928-29 style brake light switches, the reproduction junk that's been sold for the past 20+ years, are junk. Junk. They are prone to shorting out inside. In the process of testing your new stop lights, you may have unknowingly shorted out the junk switch.

There are other places for short to occur. They are easy to track down by starting at the point where the wires connect to the generator (alternator in your case). Isolate lighting system from ignition system. Work from there.

If you had the instrument panel off (for a 12 volt ammeter -- there is no such thing) you can have a short in there to the gas tank.

Be systematic and you will find your problem.

Charlie Stephens · 02-24-2019, 11:11 PM

Buy or borrow an inexpensive analog (NOT DIGITAL) voltmeter and start looking for voltage where it should be.

Charlie Stephens

Jim/GA · 02-24-2019, 11:16 PM

Charlie is right.

Or a basic test light where you connect a wire with an alligator clip to ground, and then go around and touch each post, nut, or screw one step at a time -- looking for power where it is supposed to be -- until you don't find it.

Here's the one I carry:
https://www.amazon.com/Podoy-Voltage...tph_263_lp_t_3

Badpuppy · 02-25-2019, 09:42 AM

Without the fuse the cause would have been immediately obvious from all the flaming wires. Give yourself a pat on the back for installing one.

jrelliott · 02-25-2019, 11:51 AM

If you install a new fuse and it blows, as other have said stop light switch is a probable cause. To find the real cause get a small 12V bulb and attach alligator clips with wires to the bulb on both the base and center contact. Connect the two alligator clips across the fuse mounting without a fuse installed. If the bulb lights and you have nothing on you have a problem somewhere. You can verify the brake switch if the bulb stays on after depressing and releasing the brake pedal. When the bulb goes off and nothing on, you are good to go.

katy · 02-25-2019, 12:04 PM

Quote:

Originally Posted by Hunterspeedandkustoms

Gotcha Jim. Yes changed from positive ground to negative ground. I eyeballed the fuse at the starter and it looks good. Tomorrow night will change it out or bypass it to rule that out as a factor.

Just because a fuse looks good doesn't mean it is. It needs to be tested, either in place w/a voltmeter or test light, or removed and tested w/an ohmeter.

Jacksonlll · 02-25-2019, 06:58 PM

Look around for a master switch and tighten all battery connections. If

1crosscut · 02-25-2019, 08:54 PM

Do you have power to the starter and can turn the engine over? If you do then it is a good chance the small fuse mounted to the starter is indeed bad. A simple test light is your friend in a situation like this.

Hicktick · 02-26-2019, 09:39 PM

Get a test light and start testing for power and grounds .

When I taught automotive tech , I had bulbs I had painted the contacts with
clear finger nail polish , really makes them test it all .

02-24-2019, 08:09 PM	#1
Hunterspeedandkustoms Junior Member Join Date: Feb 2018 Location: Texas Posts: 14	Upgraded to 12v Elec, Then No Power Did a pretty basic conversion from 6v to 12v today. New 12v battery, 12v alternator, 12v coil, 12v amp gauge, new 12v bulbs. Got the car to fire up after doing the conversion, all seemed well. Started changing the tail light bulbs, got the running lamps working successfully first, then started on the brake lights. During testing the brake lights (unsuccesfully) I lost power. Running lights don't work anymore, turning the key I have no power to attempt to start the car again. Confused. Battery is showing 95% charge. Short circuit somewhere? But why suddenly? Only thing I can think to do is start over fresh on the battery connections to ensure I have a really solid ground and tight connections on the poles. Thoughts?

02-24-2019, 08:18 PM	#2
Ruth Senior Member Join Date: May 2016 Location: Glide, Oregon Posts: 1,339	Re: Upgraded to 12v Elec, Then No Power Really stupid question on my part but I have to ask. Do you have a main fuse? To lose everything so fast the first thing I thought of.

02-24-2019, 09:51 PM	#3
Hunterspeedandkustoms Junior Member Join Date: Feb 2018 Location: Texas Posts: 14	Re: Upgraded to 12v Elec, Then No Power Not a stupid question at all. That's a helpful suggestion I hadn't thought about Ruth. I'm a recent owner of this coupe and I'm not 100% sure about the ins-and-outs of this electrical system. Best I can tell, there is no master fuse. The only fuse on it seems to be the one I installed a while back off the starter. While I had hoped to avoid it, sounds like I may just need to go through the wiring thoroughly.

02-24-2019, 10:24 PM	#4
Jim/GA Senior Member Join Date: May 2010 Location: Young Harris, GA Posts: 1,821	Re: Upgraded to 12v Elec, Then No Power What year is this vehicle? Did you change from original positive ground to negative ground when you changed to 12 volts? The "master fuse" that Ruth asks about IS the one you installed on the starter a while back. __________________ Jim Cannon Former MAFCA Technical Director "Have a Model A day!"

02-24-2019, 11:02 PM	#5
Hunterspeedandkustoms Junior Member Join Date: Feb 2018 Location: Texas Posts: 14	Re: Upgraded to 12v Elec, Then No Power Gotcha Jim. Yes changed from positive ground to negative ground. I eyeballed the fuse at the starter and it looks good. Tomorrow night will change it out or bypass it to rule that out as a factor.

02-24-2019, 11:11 PM	#6
Jim/GA Senior Member Join Date: May 2010 Location: Young Harris, GA Posts: 1,821	Re: Upgraded to 12v Elec, Then No Power Sponsored Links (Register now to hide all advertisements) Slow down, ace. Fuses blow for a reason. If you bypass it, you will end up with an electrical fire. You need to determine why the fuse blew. I asked what year car this is because the 1928-29 style brake light switches, the reproduction junk that's been sold for the past 20+ years, are junk. Junk. They are prone to shorting out inside. In the process of testing your new stop lights, you may have unknowingly shorted out the junk switch. There are other places for short to occur. They are easy to track down by starting at the point where the wires connect to the generator (alternator in your case). Isolate lighting system from ignition system. Work from there. If you had the instrument panel off (for a 12 volt ammeter -- there is no such thing) you can have a short in there to the gas tank. Be systematic and you will find your problem. __________________ Jim Cannon Former MAFCA Technical Director "Have a Model A day!"

02-24-2019, 11:11 PM	#7
Charlie Stephens Senior Member Join Date: May 2010 Location: Southern California Posts: 7,032	Re: Upgraded to 12v Elec, Then No Power Buy or borrow an inexpensive analog (NOT DIGITAL) voltmeter and start looking for voltage where it should be. Charlie Stephens

02-24-2019, 11:16 PM	#8
Jim/GA Senior Member Join Date: May 2010 Location: Young Harris, GA Posts: 1,821	Re: Upgraded to 12v Elec, Then No Power Charlie is right. Or a basic test light where you connect a wire with an alligator clip to ground, and then go around and touch each post, nut, or screw one step at a time -- looking for power where it is supposed to be -- until you don't find it. Here's the one I carry: https://www.amazon.com/Podoy-Voltage...tph_263_lp_t_3 __________________ Jim Cannon Former MAFCA Technical Director "Have a Model A day!"

02-25-2019, 09:42 AM	#9
Badpuppy Senior Member Join Date: Dec 2017 Location: Guthrie, OK Posts: 1,145	Re: Upgraded to 12v Elec, Then No Power Without the fuse the cause would have been immediately obvious from all the flaming wires. Give yourself a pat on the back for installing one.

02-25-2019, 11:51 AM	#10
jrelliott Senior Member Join Date: May 2010 Location: Pine, AZ Posts: 794	Re: Upgraded to 12v Elec, Then No Power If you install a new fuse and it blows, as other have said stop light switch is a probable cause. To find the real cause get a small 12V bulb and attach alligator clips with wires to the bulb on both the base and center contact. Connect the two alligator clips across the fuse mounting without a fuse installed. If the bulb lights and you have nothing on you have a problem somewhere. You can verify the brake switch if the bulb stays on after depressing and releasing the brake pedal. When the bulb goes off and nothing on, you are good to go.

02-25-2019, 06:58 PM	#12
Jacksonlll Senior Member Join Date: Jul 2012 Location: Michigan-- Member of Oakleaf of MARC Posts: 1,686	Re: Upgraded to 12v Elec, Then No Power Look around for a master switch and tighten all battery connections. If

02-25-2019, 08:54 PM	#13
1crosscut Senior Member Join Date: Feb 2011 Location: Lincoln, Nebraska Posts: 1,909	Re: Upgraded to 12v Elec, Then No Power Do you have power to the starter and can turn the engine over? If you do then it is a good chance the small fuse mounted to the starter is indeed bad. A simple test light is your friend in a situation like this. __________________ Dave / Lincoln Nebraska

02-26-2019, 09:39 PM	#14
Hicktick Senior Member Join Date: Aug 2011 Location: Hickory Tavern , SC Posts: 422	Re: Upgraded to 12v Elec, Then No Power Get a test light and start testing for power and grounds . When I taught automotive tech , I had bulbs I had painted the contacts with clear finger nail polish , really makes them test it all . __________________ Sometimes I want to say ,,You should have bought a Shay.