I made my own wire harness to fit my '37s needs. No fuses, all self-resetting circuit breakers. My truck has A/C, lights, and horns, no other accessories so running wires was easy.
I ran all the wires to a box under the seat, if something goes wrong, I lift the seat to check for problems, not crawl under the dash. I helped scrap out a school bus, so I had tons of wire all numbered and color coded. In 26 years, I haven't had one issue with the electrical system, not even a light bulb out. I ran a ground wire to every light from a main ground stud just off the battery, so no need to grind paint off or worry about grounding issues.
Plan ahead for future accessories, I knew at some point I was adding A/C, so I added a heavy power and ground wire up to the dash area when I made the harness, same with ignition, I used a 12 gauge wire to the points distributor knowing I was adding HEI down the road when money became available.
Since it's a truck, add a trailer light harness plug, you may never use it, but the next guy might.
The original harnesses didn't use fuses, they were not needed. The head light switch had a built in circuit breaker of fuse, nothing else was installed that needed fused.
Last edited by Joe H; 04/25/2026 1:18 PM.
