When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi,
I have a 1984 Ford F-250 with a flatbed and I just wired in new taillights and used the factory wiring diagram to wire them in correctly. I had the driver side wired in and working fine, then when I wired in the passenger side they worked but when the key was on and the lights off the driver side was still on and the passenger side was off but I fixed them. I wired in 3 lights on my headache rack and then with just the key on or the lights turned on the passenger side looked like I was hitting the brakes and the driver side and headache rack were off but if I hit the brakes everything lit up. Does anyone know what would cause this and how to fix it?
Thanks for any help!
Double check the grounds at the tail/brake lights.
If the headache rack lights come on with just the "Key On it sounds like you might be back-feeding the lighting circuit via the headache bar wiring. Try disconnecting that and see how it works.
If you used LED lights, that can be a problem and cause "ghost" glowing of the lights. It comes from the cruise control and other circuits that are tied into the brake circuit. The old style lights take so much current to glow, that small voltage normally there does not light them up.