lights out

[classic67]

Ok so I am lost. I have been tracking down a wiring gremlin for a week now. My truck has been sitting for about seven of the last eight years. I turn on the lights and the headlights come on but one os really dim and no tail or brake lights. I had to replace one of the tail light buckets because of corrosion. Sometimes they come on and stay on even if the key is out. I don't understand if ts a ground or a power issue.. I'm not looking to spend five hundred on a new harness right now so I'm trying to patch it up the best I can

[Canonman67]

One thing you might try is replacing one circuit at a time. Like run the rear lighting circuit to a point where you'll install a disconnect. I did this to a '49 Dodge way back when and in six months of repairs I found I had replaced the entire harness.

[sargentrs]

I had similar issues with my '64 Fairlane. First it was the headlights. One morning she just decided she wanted all four headlights on all the time, and the brights were really dim, instead of 2 on dim and 4 on bright. Replacing the dimmer switch didn't help. Found a broken ground on the passenger side at the radiator support. Put a new ring terminal on it and fresh screw into the sheet metal and problem solved. Next, the driver's side turn signal went really dim. Still worked, just dim. Replacing the bulb didn't fix it. Took the assembly out, cleaned the threads on the mounting studs and the outside edge where it contacts the bumper. Reinstalled and problem solved. First step would be to check your grounds and grounding contact points. Headlights and taillights are mostly on different circuits. However, they do have 2 places in common, headlight switch and turn signal switch. Focus on the headlights first, they've more isolated. Verify your grounds and your power sources, one light at a time. Here's some diagrams that might help.

http://www.fordification.com/tech/wirin ... ghts01.jpg
http://www.fordification.com/tech/wirin ... ghts02.jpg

[Ranchero50]

Ditto, grounds and corrosion cause all sorts of 'gremlins'. A decent multimeter is your friend. Check for voltage between the housing / ground wires and the body / battery. That will show ground problems.

A dab of heavy grease on clean ground spots will keep corrosion at bay.

[classic67]

Thanks guys I've redone the wiring from the axle back. I still have alot of ground to cover but its an issue that I'm not familiar with.

[66f250cs]

JMHO, but from my experiences with old stuff, it's usually a poor/no ground connection. Usually, not always.

[classic67]

Well it got worse. I lost a headlight on the way home the other evening and then it lost spark on the way to work. So I'm not site sure what the [censored] is going on. I'm not that good with wiring to begin with but this is getting dumb.

[Ranchero50]

Welp, good time to learn and start understanding the what's and why's of electrical problems.