Hi Guys

While I can generally figure things out mechanically, I've never had to do much electrical work.

I've got a short somewhere in the brake/turn signal circuit of my '51. I noticed last week that I had no brake lights and no turn signals. After a little investigation, I found an in-line fuse under the dash had blown, so I replaced it. Things worked fine, then I went for a ride, and the fuse blew again by the time i got back.

The fuse I found (there are only two or three in the whole truck) seems to feed only the turn signals and brake lights.

This may or may not be related, but when I replaced the fuse, and put the 4-way flashers on, the right signal light was flashing much more dimly than the left. (I assumed it was a bad bulb). Also, I replace my master cylinder when I did a brake upgrade a couple of of months ago, and installed a new pressure-activated brake light switch at that time. I checked the terminals and everything looks fine. I checked the light sockets themselves - there's a little rust and dirt, but where the contacts are doesn't look too bad.

All this being said, the running lights work fine. The tail lamps have two bulbs - one single contact and one with two contacts/two filaments.

Obviously, I'd prefer to fix this myself. So, a few questions:

First - any suggestions on where to start? I do have a multi-meter.

Second - the last thing I want to do is to take it into a shop, where they'll try to milk me out of a fortune to re-wire the truck. For a couple hours labor to have a shop patch an already ugly electrical system, I could spend the same amount on one of the EZ-Wire kits that i see for $160. I understand they are quite simple to install yourself - has that been your experience?

Any assistance you can provide would be much appreciated.

Brian
Winnipeg

 

If you are blowing fuses, you have a short somewhere - maybe intermittent, but definitely a short.

I had a similar problem recently and it turned out to be a wire pinched under the exhaust clamp bracket. Don't know how it got under there. Look for the simple stuff first.

Also, I had to add a second ground wire from the pass. side light housing direct to the frame before my lights all worked equally.

 

Brian,

You need to trace the wire from the inline fuse all the way back to the tail lights to find the short. The wire may have gotten squeezed or pinched somewhere along the way. Look for obvious places where this could happen. If the brake/directional signal wires are wrapped in a harness with the tail light wires, it might be easier just to cut the wire and run a new one all the way back or rerun all the light wires to the rear. Also, be sure the inline fuse is large enough to carry the current. I'd use at least 20 Amps. A 10-15 Amp fuse might be marginal.

Vern

 

Also, when you mentioned that one light gets dimmed, seems that not enough current is getting to the lights. One, how much current do you need for the lights, 10 amps then I would use 16 gauge, 15 amps I use 14 gauge. ALso, what might cause the dimmed light is a lose connection. Whether you use solid or stranded wire does not matter.

 

Brian,
Intermittant electrical problems are a booger so don't get discouraged. Another troubleshooting method is to temporarily bypass your wiring with a "test wire". Go to wire terminals or junctions you already have, undo the termination and install your test wire. If it works, you bypassed the problem and can start trying to narrow down the area. Obviously you have to have the problem existing for this to work. If its intermittant, this can be hard to do.
Always always do the easy stuff first.

Good luck and let us know what the answer is when you fix it.

Reed

 

Thanks for the advice guys - sounds like there's no easy solution other than grunt work and tracing wires. I'll let you know what the problem ends up being.


thanks
brian

 

I had this happen once. If you have a signal switch that is on the steering column, then that may be where your trouble is. All the wires to stop lights and signals go into it to make the connections to signal instead of stop light. One of may connections had come lose inside the switch. A real headache.

 

Actually, if this is the case, it'll be an easy fix.....the turn signal unit is an old, cruddy aftermarket cheap thing that secures to the column with a pipe clamp.....and one of the local parts places has a bin full of them - new ones - chromed up nice - for (if I recall correctly) about $5 each. Might be a good first-try.

Brian

 

Hey guys being an old thread I want to hightjack it.
My f1 just started blowing the headlight/taillight fuse.
I have the pull -out style switch for the head lights,tail lights and dash clusters with one inline fuse.
the truck came with some fuses and i have been using them but i could not read the amperage,So i went to buy a set of 4 30 amp fuses and it keeps blowing them.
I might have to start looking in to a complete EZ KIT too.
The questions are:
1-would a bad headlight cause this??
2-are all these lights to much for the fuse??
Thanks in advance for your help

 

I'm no electrical whiz, but would not think that a bad headlight would cause a 30 amp fuse to blow. As for as all the lights through one fuse, normally the directional lights are are on a dedicated fuse (20) amp. as this was an add on for this truck. Did the problem start after some recent changes to the electrical system or has it always been a problem? My guess is if it suddenly started, would be a short some where in the system. Hopefully, someone will chime in with more knowledge or can explain it better than I.

Gil

 

The signals are in a differnt fuse.
The problem just started.thanks tho

 

Take a good look at your light switch. They have a tendency to overheat as time go by. Sometimes they start fires. chuck

 

Also dont forget each lite has its own ground, wich a missing ground could possibly cause a dim lite. I shot low voltage circuits for 34 years, dont let it scare you. your mutimeter is great but a 12 or 6 volt test probe that has an aligator clip on one end wich you clamp to ground then touch the probe looking for voltage is very handy and cheap ( i dont know how easy it is to find a 6volt one) ther are many schematic drawings in the archives i just dont know how to bring them to post. just remember each circuit needs a battery source and a ground wich is usually to the frame or body via a mounting screwin some cases. Each blinker shoud have its own wire to its bulb, and then to ground. IM not good at explaining so i hope this helps and not hinders.

 

I'm thinking the underthebridgejim is on the right track. If nothing else changed and all of a sudden the system is blowing fuses, I'd look for corroded ground wires. If you get a bad connection due to corrosion, the current draw for that circuit will increase....at some point, the fuse could blow. In the headlight bucket, there is a ground wire attached to the bucket with a screw. Check those...clean up any rust and replace the loop terminal on the end of the wire if it looks bad....you can even get rust where the terminal was crimped onto the end of the wire. Ground is a relative term on a positive ground 6v system, but I'm talking about the wire that attaches to the frame. Also check the supply connections while you're there.

You can isolate it a little by disconnecting individual lights & see if the others work normally.

Dan

 

Thank you guys i got it figured out.I did what Hellfire Jim told me and it worked.I unplugged all the wires from the switch after checking all the grounds and started from there. I think i think the switch was so loose that the fuse end was grounding with the dash but I dont know.I even used a 10 amp fuse and it didnt blow.thank God It only took me 5 minutes I hate electrical work.
Thank you guys you give great advise too. thanks