Break light issue

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Mar 8, 2025 | 10:04 AM

Daniel Yosef

Thread Starter

Mountain Pass

Joined: Dec 2024

Posts: 134

Likes: 6

Break light issue

I have a problem having only one break light working and the one that works stays on all the time even with key off. Please help

Mar 8, 2025 | 03:41 PM

Green72F250

Tuned

Joined: Jun 2014

Posts: 494

Likes: 144

From: Colorado Springs

If I recall correctly your truck is a 1967. You might want to put your information in your threads to help get a better answer to your questions. The 1967 brake light switch is different than the 1968-72 brake light switch. I know on the 68-72 switch you can adjust it, I'm not sure on a 1967. Check to see if you can adjust the brake light switch so it doesn't stay on all the time. In regard to only one brake light working, the things I would check would be that the bulb is good, that the socket for the bulb is clean, and that you don't have a wire that is cut in the rear taillight harness. Most trucks I have come across the taillight harness has been butchered to add in trailer lights. Maybe someone with a 1967 can chime in on whether there is an adjustment for your switch. Here is a diagram that shows the brake light switch, the 1967 switch is in the upper left-hand corner. Part number 13480 in the diagram.

Mar 8, 2025 | 05:37 PM

1TonBasecamp

Lead Driver

Joined: Jul 2017

Posts: 9,606

Likes: 1,175

From: San Jose, CA

Any other modifications to the truck? There is not always full power all the time to the rear harness, but if yours does have a powered circuit back there, then check all connectors and wires from the firewall back.
If you have dual exhaust, quite often it's too close to the wires and heat will have it's way with some of them. If there is a trailer wiring connector, they go bad now and then and will short across wires. If the bundle got pinched at some point during some work or maintenance or modification, that's another source to look for.

Good luck.

Paul