Fues-Block For My Head-Lamps

[rfitzpatrick]

OK, I've a heated discussion between myself and my Model A CrewChief (H Jones) -- there's yellow wire coming out of my head-lamp switch going to my alternator as it's source of power -- am I right? If I were to install a seperate fuse-block, would this allow me the same protection as leaving it routed to the starter fuse-block? Would this cause any power disruptions to any other electrical system, limited as they already are? What I'm wanting to accomplish is having my entire lighting system on a seperate fuse-block so that if a head-lamp shorts, it will not shut me down -- the main thing at risk here is Mr. Jones pride.


Thanks

[Jim/GA]

That is an excellent idea and you have chosen the correct place to put the fuse.

Then, if you have a short in the lighting system, it will not kill your ignition, just your lights. You can limp home without lights and figure it out.

I know one person that has sent power back to his brake light switch with a new, dedicated wire that does not feed off of that yellow wire going into the headlight switch. It is fused and feeds off the post in the terminal block on the firewall that holds the yellow/black wires. This is so that if the fuse that you add to the headlights blows, he still has brake lights when driving. Not a bad idea, but more of a deviation from original, which makes troubleshooting more difficult in the future.

[Badpuppy]

With standard wiring there are two yellow wires from the gen/alt heading downward. One goes to the lighting switch, the other to the horn. You can add an inline 20A fuse/breaker at the alternator to serve them both. But as Jim implies, if it opens you lose all the lights.

Original purpose of the battery fuse was to protect it from discharge caused by a stuck cutout contact. It never provided protection to anything else. Doesn't hurt to leave it in.

[rfitzpatrick]

Jim
While I can see this deviation from original -- it would also allow me to trouble-shoot the electrical systems indenpendently -- as when I have an electrical problem, I quit driving until it's located and repaired. If it's the head-lamps, I would still drive, just not at nite.
Thanks

[Jim/GA]

The deviation I was warning about had to do with adding a new power feed to the brake light switch. That's a deviation.

The addition of a fuse where you are talking about is very clean and obvious. Not a deviation, to me. Just common sense.

And I would fuse the horn power feed wire separate from the feed to the light switch. With that horn wire hot all the time and having the ends just clipped into the horn motor, it is very possible for the wire to get shorted out inside the horn when messing with it or when driving down a bumpy road. You want that fuse to blow before your wiring starts to burn.

So you are really talking about adding 2 fuses there. I fully support that. Use weatherproof fuse holders and you are good to go. Yes, it also helps with troubleshooting.

Remember, if you drive during the day with the fuse to the light switch out, you have no brake lights.

.

[Ruth]

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I added a 20amp circuit breaker to the yellow wires coming from the alternator to the light switch. It is hidden in the frame rail next to the alternator.

[Bob C]

Originally Posted by Ruth

I added a 20amp circuit breaker to the yellow wires coming from the alternator to the light switch. It is hidden in the frame rail next to the alternator.

Looks like your light switch is upside down.


Bob

[Ruth]

Originally Posted by Bob C

Looks like your light switch is upside down.


Bob

Haha, Good eye Bob. I had a Brain Phart while putting the switch on from under the car. That is a old picture and it has since been "repaired". I have also added a PowerGen since then.