Electrical issues- tail lights/light switch
 

Hi, new problem with my tail light circuit. My headlights turn on, but my taillights and my dashboard instrument lights don't. Is this a problem in the switch? I checked the fuses they all look ok except for one little 5 amp one that hasn't had power since i got the truck but i replaced it anyway and its still the same. I did notice that this morning when i switched my windshield wipers on my hand pushed the headlight knob in one click and the dash lights (and i'm assuming the tail lights) illuminated, but they went back out when i pulled the knob out to turn on the headlights again. My brake lights do work. I can't get pulled over cause i failed inspection... last july. Thanks guys.

Headlight fuse is part of the switch, other lights have a fuse in the panel. If fuse is ok, it could be the switch. Given that messing with the knob seems to make a difference, I'd lean towards replacing the switch. A pain to get to but not too bad and not expensive. Brake lights are controlled by another switch entirely.

I wouldn't drive it at night until you get this fixed; tail lights out are not good and make for an easy interdiction stop. I've gotten plenty of arrests that stemmed from a stop for defective tail lights..

If the problem is what I think it is, your front running lights are not working either correct?

yes- no front running lights. and i actually just drove from my girls house with all lights on, i jiggled the damn switch until i got it to work. Napa was the only store that said they got a switch for me tomorrow, so i just have to make it to work before dawn in the morning and i'm good. Now the last piece of the puzzle is getting that stubborn switch knob off so i can remove the plastic dash cover ha. hoping the sawzall stays in the garage for this one.

That's up in the Sticky and/or FAQ section at the top of this forum..

I replaced the switch today.. It's doing the same thing. Headlights work but no taillights running lights or dash. I checked the wire connector, and followed the advice in previous threads about checking the tan and white wire on the connector. The wire looks good, the connector is corrosion free. The tail lights lights don't illuminate when i wiggle each wire on the harness one by one.

They do however come on when i pinch the switch firmly in the middle right on the little knob release pin and wiggle the switch in and out in a certain way. If I guide the switch slowly just halfway between the running lights and headlight setting all the running tail dash lights come on.

Is it really possible that i bought a switch with the same exact problem? It's a notably crappy switch from napa. that just seems like too strange a coincidence but i don't know

I suspect the headlight switch isn't the problem....

See what Dave has to say, I gotta get outta here and head home right now....

Perhaps a bad connector? I hear they sell new ones with pigtails. Maybe try cleaning the connector block

I have the same problem with a g.m. 1/2 ton, I always thought it was the switch. I just wiggle the switch till the dash lights come on, I've been doing that for over 20 years. I'm surprised a new switch didn't solve your problem.

i swear its the switch unless theres a problem with the ground... which one of these connectors is the ground? maybe the burnt looking red one?

OK. its definitely not the switch. The third switch proved me wrong hah. I know it must be the electrical connectors. Each socket has a wire with a slide terminal that locks into the plastic harness. When i pull out the tan/white one it looks clean and good. I even gave it an extra squeeze with a clamp to make sure it was tight. There was another wire in there. It was a fatter wire red with a stripe. i forget what color stripe but it looked burnt so i tried to scrape it a little and gave it an extra squeeze too. It really doesnt look corroded from what i can tell but I don't trust my eyes because that would leave me at a dead end with no explanation of why this is happening..

What I really want to do is just replace all of these little metal terminals. Does anyone know how I can find the exact type of locking female slide terminal I'm talking about? I just want to replace the eight of these or hardwire a whole new harness in and see where I'm at.. Or maybe someone knows a good way to clean these existing terminals?

Your problem is the tan/white. It has no power. You have already checked the connector area. I would step back and first check the fuse. This wire has it's own fuse. If the fuse is good, then get a testlight and probe the tan/white, it does not have power for some reason.

The reason you can put the switch "midway" and it works is because you are crossing up the contacts inside the switch. Most people do not realize there are several different sections to this switch, with different power supplies. They think(logically so) that if the headlights work, they are getting power to the switch. But that is not true, the headlights get there power from a different circuit. The running lights get their power from another different circuit/fuse. When you put the switch midway, you are bridging the circuits inside the switch, using the headlight power to run the running lights.

Keep after that tan/white. Check it for power.

I have a Haynes manual, but I have no way of posting a picture of it. The red /yellow stripe wire goes to the dimmer switch. The tan/white wire, that Franklin 2 mentioned , should go to the bottom right fuse. Check that fuse, possible broken wire on the back side of the fuse box, if there is no power. Check all other fuses first, some don't have power unless the key is on. The other wires that go to the fuse box are, Lt. Grn./yellow,Lt. Blu./Red and Blk./Orange.