Hot fuse

[1948Skip]

Ok fellas,

I was on my way back home from a peashes and ice cream car show in Oley Pa last night when I lost my running lights. I had to run a couple miles to get to a safe place to get off the road. I had enough light from my buddy who was folllowing me to make the couple miles.

Here is my problem. When the lights went out I reached under the dash at the head light switch and got burnt from a hot fuse holder. Remembering from my past other P-15s I have owned, the fuse and holder was hot on these cars also. I could never find a good answer as to why.

What say you guys. Pull your head lights on and after a few minutes of running feel the fuse holder and see if it is hot and let me know what you find. I would appreaciate your answers and help.

Skip

Edited August 15, 2010 by 1948Skip

[BobT-47P15]

When my headlight switch/fuse holder got hot......I then discovered I had

hooked up a couple of the wires to it wrong. My lights would go out after

a while, etc. So, based on my experience, I would say get your wiring

diagram and re-check how your wires are hooked to the switch.

Past that, I don't know unless you have like a bare or broken wire

that's grounding.

[1948Skip]

Bob T

The wiring has never been touched in the last 62 years and I know for sure in the last 22 years since I have the car. I will however take your advice and start checking individual wires for any shorting or heavy current draw.

What say you other drivers?

Skip

[Oldguy48]

My suggestion would be to remove the headlight switch (disconnect the batrtery first), and give it a thorough inspection. The fuseholder is getting hot because there isn't a good clean solid connection between the fuse and the fuseholder. You might find some tarnish or corrosion in there that needs to be cleaned up. Tarnish or corrosion prevents a good low resistance connection, and any resistance present produces heat when current is trying to flow through it. Sometimes, the fuse will fail due to the heat, not because of a short or overcurrent condition. A brass bore cleaning brush for a .22 or

.25 caliber firearm might just do the trick for you.

[greg g]

Might be a short somewhere between the switch a d the lights or corroded grounds. A dead short will usually blow a fuse withour a lot of heat, heat is a symptom of resistance.

[1948Skip]

Thanks Guys. This will give me a lot to look for. I like the idea to use a .22 cleaning brush in the fuse holder. I'll let you know what I find in my clean up and testing.

Skip

[TodFitch]

My suggestion would be to remove the headlight switch (disconnect the batrtery first), and give it a thorough inspection. The fuseholder is getting hot because there isn't a good clean solid connection between the fuse and the fuseholder. You might find some tarnish or corrosion in there that needs to be cleaned up. Tarnish or corrosion prevents a good low resistance connection, and any resistance present produces heat when current is trying to flow through it. Sometimes, the fuse will fail due to the heat, not because of a short or overcurrent condition. A brass bore cleaning brush for a .22 or

.25 caliber firearm might just do the trick for you.

I've had something very like this be a problem on my car when it was about 45 years old: The fuse on the car mounts on the back of the ammeter with the fuse vertical. I had a whole succession of fuses fail, always at night with the lights on. And in all cases the fuse link itself was intact but the fuse just stopped conducting. I eventually figured out that there was enough corrosion on the brass conductors, rivet and fuse holding clips that the localized heating (power draw across high resistance connections) that is was melting the solder that held the end caps of the fuses on.

I took the ammeter and fuse holder off, cleaned the clip, rivet and connecting strips then soldered them to assure that the corrosion would not return. Haven't had that problem again in the last 30 years on that car.

If the fuse holder is getting hot then there is there is either too much current (short or wrong bulbs installed) or too much resistance (most likely corrosion).

[james49ply]

My 48 did the same thing, the fuse is attached to the headlight switch and the rivits got loose causing high resistance. Due to the fact that I drive mine as primary transportation, I opted to run a seperate wire with fuse bypassing the origional, I used a ten gauge wire with 30 amp spade fuse, have had no problems and the wires stay cool. my final solution will be to install and wire in a fuse panel to protect the existing wiring as it is in very good condition.

[Jim Yergin]

I have installed headlight relays (high and low) to minimize the current that passes through the switch.

Jim Yergin

[John Reddie]

Yes relays really work in these older cars. It is a long way from power to the headlight switch to lights. Resistance can occur in these systems as they age. The relays would eliminate the hot switch issue.

John R