Electrical troubleshooting

[bunnyc]

A good ground is essential. Yep.

[jax55]

So Bunny, are you saying you took awhile to find an electrical problem due to a bad ground? Tough to find and frustrating to pin down,

[bunnyc]

Yes, tail light and brake light not working. Checked bulbs: OK, then started at the cutout switch and worked my way back. Hours with my multimeter and jumper wires. I'm old and slow.

Final outcome: The three carriage bolts holding the tail light bracket (I just have the one on the drivers side) to the fender and the inner fender had rust. The heads of the bolts looked good, painted. The bolt threads, lock washers and nuts were bad.

Finally found it when I checked the resistance between the tail light mount bolts and the bracket carriage bolts; xxx K ohms. That was my bad ground. Cleaned the inner fender and new bolts. Good to go.

[BILL WILLIAMSON]

Chief always "fished" a ground wire through the tail light loom, attached it inside the light & to a good hidden spot on the BODY/FRAME. He did the same on the headlights, also!
Bill Grounded

[JOHN CT]

Originally Posted by BILL WILLIAMSON

Chief always "fished" a ground wire through the tail light loom, attached it inside the light & to a good hidden spot on the BODY/FRAME. He did the same on the headlights, also!
Bill Grounded

I've done the same thing as the Chief. Ran separate ground wires for all lights,and ran a extra cable from the transmission to the battery. 20 years and I never had a ground problem
I don't do things right all the time,but this time I did

[jax55]

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X2 after chasing the same tail light ailment. No further problems.
Lesson learned.

[jrelliott]

I also did what Chief and others have done on the extra ground wires on tail lights, and headlights. When attaching the extra wire to the frame or body used a star washer and cleaned the area under the star washer so there was good mechanical contact. Extra grounds to engine are also provide excellent paths for the current to flow unimpeded.

[SeaSlugs]

Originally Posted by jrelliott

I also did what Chief and others have done on the extra ground wires on tail lights, and headlights. When attaching the extra wire to the frame or body used a star washer and cleaned the area under the star washer so there was good mechanical contact. Extra grounds to engine are also provide excellent paths for the current to flow unimpeded.

agreed, todays super paints make great electrical insulators to where star washers and lock washers dont bite thru them or if they do very poorly.

[H. L. Chauvin]

FWIW:

For anyone looking under search for this title of Electrical Troubleshooting:

If your Model A headlights, cowl lights, brake lights, tail lights, and "trailer lights" on vintage trailers and/or modern trailers are "not" functioning:

From so many past experiences of light malfunctioning cases, in 99% of cases it is usually poor electrical grounds, e. g., electrical ground disruption caused by metal oxidation at metal electrical contact connections, excess paint at metal electrical contact connections, and/or loose connections at these same locations.

[California Travieso]

Originally Posted by bunnyc

Yes, tail light and brake light not working. Checked bulbs: OK, then started at the cutout switch and worked my way back. Hours with my multimeter and jumper wires. I'm old and slow.

Wouldn't have been better to start at the tail light instead of at the light switch?

David Serrano

[bunnyc]

Originally Posted by California Travieso

Wouldn't have been better to start at the tail light instead of at the light switch?

David Serrano

Hindsight is 20/20

[SeaSlugs]

Originally Posted by California Travieso

Wouldn't have been better to start at the tail light instead of at the light switch?

David Serrano

depends whats easiest to get to, but yes if you have a non working component first thing to check is the fuse if it has one, then go to the non working component and work your way back to where you have power and find out why it stopped.

Sometimes your lucky and its near the component, other times you trace wires back to the source to find the issue so i usually go by whats easiest to check.

[Patrick L.]

Good grounds are a good thing.

[bunnyc]

My first thought was 'what do these both have in common'. Both powered from the light switch at the end of the steering column.
I'll start at the front.
Much later I learned they share a common ground.

Those smarter than me that would have started at the rear, well, hats off to you.

[Big hammer]

Good for you! You fixed your problem with out barn help! Whats that NY saying " for get about it" arm chair electricians :-)

[H. L. Chauvin]

Per part of your reply no. 14:

"I'll start at the front." .......... and, "Those smarter than me that would have started at the rear."

In my opinion .... not necessarily ..... because this is just another fact that all Model A's are different; and, like highly trained Urologist, all Model A owners are different.

E. G., many well experienced, intelligent Urologist start at the front .... and some the rear.

Hope this makes you realize that like in the Medical Field, you proper diagnosis came with your showing us a high degree of intelligence ....... i.e., it is working !!!!!!

[Tom Wesenberg]

It's hard to know where to start when checking a problem in a circuit.
Some circuits I'll start in the middle, and if I have power at the mid point, then I've eliminated the first half of the circuit as the problem.

[BILL WILLIAMSON]

Some Guys with trailers just depend on the BALL & HITCH for a GROUND & "wonders" why folks say, "Your lights are FLIKERING"!!!
On a trailer, it's good to run a HEAVY/SEPARATE ground wire
When I wire something & worry about what gauge wire to use, I just go to the NEXT heavier Gauge. OVERKILL is GOOD, in some things!--LOL
Bill Burnsbright ---(In case you "wonder" about my last names, I LOVE to study WEIRD & UNUSUAL last names.)