The Stovebolt Site Forums The Shop Area The Electrical Bay Park light fuse keeps blowing.

I’ve examined every wire for continuity. This AAW wiring kit was installed by me about 5 years ago. There are no wonky connections.
Brake lights and turn signals all work properly. Only the park light fuse blows - repeatedly.
I need to step away and let my mind settle.
What should I do besides test each wire for ohms/continuity?'
When the fuse blows I lose front and rear park/running lights and dash lights. I thought I had a short in the license plate light but it tests ok. With the rear bulbs inserted and grounded I get right around 5 ohms for that rear circuit.
Could it be a bad light switch?

Sounds to me like an intermittent short to ground. It tests fine most of the time, but blows the fuse when you hit a bump just the right (wrong) way.

Have you traced the wires to look for wear/pinch points? That is what I would try next.

I agree. Intermittent. Funny thing is that it’s been fine for several years. I suspected my LED license plate light but so far it tests fine and I don’t see any broken wires. I think I even had it out of the circuit once when I blew a fuse, so I sorta ruled it out that way. 10A fuse.

Funny how you can fool yourself sometimes trying to trace short. Thought I was tracking a short as I kept finding continuity to ground as I moved closer to the cab. Then I realized that the front park light bulbs were grounded and I was interpreting that as a short to ground. Haha! Remove bulbs = short went away. I had continuity through the bulb filament and the bulb base was grounded.
Sure tests my abilities but so far I’ve found nothing.

I won't admit to having to done the same thing before

The usual culprits in my experience are sheet metal penetrations and sockets. If you don't see any obvious wear spots, you might try turning the lights on and wigging the wiring in different places to see if you can cause it.

I had one years ago where the isolation in the socket itself was degrading and it would occasionally short inside. I found it by wiggling the wiring going into the socket.

Check wires running close to the exhaust. I had an intermittent short. Wire crossing over the exhaust pipe would get longer as the pipe warmed it up. Eventually, it would touch the pipe and out go the lights!

One diaqgnostic tool I use routinely is a self-resetting circuit breaker substituted for the fuse while doing my troubleshooting. It saves a pocketful of money on fuses until the source of the short can be isolated, without the wire melting hazard created by bypassing the fuse, even temporarily. Ditto on looking for chafed insulation anywhere the wires go through a piece of sheet metal. Intermittent shorts can get downright frustrating! Is there a possibility you might be dealing with "not enough fuse"- - - -like maybe a 10 amp fuse where a 15 might be better? I've seen current loads cause repeated fuse failures where the normal current flow is within an amp or so of the current the fuse can carry safely.
Jerry

I assume you've checked the bulbs. If one burns out and the filament holders touch, that's a dead short. Stranger things have happened, and a bad bulb is easy to fix.
I had an instance where my blinkers on my daily driver truck didn't flash on the right side. I was SURE it was the switch and replaced that. Not fixed. I had my camper on so couldn't check the trucks taillight bulbs. Drove from Spokane WA, to Wichita KS manually working the lever for right turns. Finally had an opportunity to take the camper off and found the two filaments shorted together, so there wasn't enough current to activate the flasher because of the resistance through the turn signal filament AND the tail light filament. Replacing the bulb fixed it up.

You could try this:

1. Take out he parking light bulbs and see if the fuse still blows
If not, put them in one at a time to localize the fault

2. Disconnect the parking light connections, see if the fuse blows
If not, put them in one at a time to localize the fault

3. I have a 1957 pickup, one time I started to melt wires/fuses. Found out it was the metal wrapping on the speedometer cable contacting the back of the dash panel
and shorting a contact from a dash light to ground. A little obtuse, but something to check if you can't find the culprit.

don

Thank you for all the supportive advice. I have not found any obvious short to ground. I am convinced that is the problem, but have not found the culprit. I am most suspicious of my LED license plate light.
At present, everything is working again as it should. if the problem recurs, I will start eliminating components, starting with the license plate light.

Run your LED light straight to the fuse block. The fuse blowing is the small one
in the light switch itself? I ran my license plate light to the block that powers the dash lights.
Also new LED