No tail lights or brake lights

[donthekawguy]

On my way tonight I was pulled over for no tail lights or rake lights. My dash lights are still working. My blinkers don't work either. The blinkers do work if I have the lights off. Maybe a bad switch or fuse? Too dark to check it out tonight.

[tincan1966]

Sounds like another bad ground situation. No single switch will take out all those lights at the same time. When one circuit will work only if another is turned off, it indicates a lack of ground, because the electricity will follow the path of least resistance. Without sufficient ground the bulb cannot light up both elements. Alot of times you will notice that even though the turn signals are working, if you look closely, the opposite side may actually be blinking very dimly. That's probably a poor discription of the cause, but hopefully it helps.

The beds on these trucks doesn't ground well at all. The "body ground" from the radiator support to the battery is only really good for the front lights and cab. There are a couple ways to help this. I like to run a 4ga battery cable from the engine to the frame(the negative cable from battery is attached to engine block) Then at the rear, I will run a 10ga wire from a cleaned area of the bed to the frame. NORMALLY this will help the tail lights alot, but an even safer bet is to run ground wires from the tail light housings to the frame.

[donthekawguy]

I put a new switch and fuse in and nothing. Hit the high eam switch and I have lights. lol good enough for me.

[awbrown]

If your truck is the same as a 63 ,the wire connector for the rear lights goes through the firewall to the right of the accelerator ,you may check that.. also check that you have power to the brake light ,if it has power to the brake switch then you better start running some new grounds and clean the connectors..

[l79m20]

I had a dimmer switch go bad on my 66 and no lights worked until I replaced floor switch.

[Turkey]

I've had a lot of tail light problems and solved them by grounding each side of the bed to the light "buckets". I have read that a lot of people on here have had the same issue and reluctantly did not perform the procedure, and tried a bunch of other things with no success. Go ahead and ground the sh!t out of the rear and you will see a difference.

[donthekawguy]

I'm hoping to put my new rear end in next week so when I have it up in the air I'll run grounds to everything and also check all the connections and wiring. I hope it will work until Wednesday or so. I have to go get my new compressor and also have a couple of car get togethers. It should be ok till then. Thanks for all the help!

[Brad54]

Originally Posted by l79m20

I had a dimmer switch go bad on my 66 and no lights worked until I replaced floor switch.

I had the dimmer switch go out and burn some wires.
At the same time, one of the contacts in the Bakelight headlight switch housing came lose and would bounce around inside the housing when I'd hit bumps... burned up several wires.

I HIGHLY recommend just replacing the whole wiring harness. I went with one from American Autowire and love it.

-Brad

[donthekawguy]

Originally Posted by Brad54

I had the dimmer switch go out and burn some wires.
At the same time, one of the contacts in the Bakelight headlight switch housing came lose and would bounce around inside the housing when I'd hit bumps... burned up several wires.

I HIGHLY recommend just replacing the whole wiring harness. I went with one from American Autowire and love it.

-Brad

I'm hoping to replace the whole harness sometime. I'm going to school for my CDL and will be going to ND and will be making some real money by June or so then I will have the cash to do it right. I just hope it works until then.

[donthekawguy]

Damn went out tonight to drive the truck to work and no tail lights or brake lights again. Pulled the light switch and no headlights either. Stepped on the dimmer switch and the headlights came on still no tail lights. I'm thinking the dimmer switch is bad. The other night I stepped on the dimmer and the high beams came on and the light in the dash came on. Now nothing but the headlights do come on. Grrrrrrrrrrr! Looks like I will be chasing ground problems tomorrow. Good thing it will be 68 and sunny!

[azdude1964]

dude it your turn signal mech. i had the same problem. fixed it.

[azdude1964]

check the wires that run up the colum

[tincan1966]

The dimmer switch has absolutely nothing to do with the tail lights, same as the turn signals. They are all different circuits.

Dimmer switch could be a problem with the headlights only coming on in bright. Can easily be tested with a test light. With the headlight switch on, test the wire in the middle (top) of the dimmer switch connector.If no 12V there, the problem is between the H/L switch and dimmer switch. If it has 12V,either the high or low beams should be on. IF neither lights are on, then test the tan wire at the dimmer switch(this is low beams)If no 12V there, then test the green wire. If still nothing, then operate the switch and restest the tan and green wires for 12V. If nothing on either tan or green, then dimmer switch possibly bad. If either or both have 12V but still no headlights at all, the problem is between the dimmer and the headlights- I'd check the firewall connection and the one at the radiator support for corrosion. Use the test light to test the wires on each side of the connectors-that will help you narrow down the bad wiring.

Turn signal switch can affect turn signal operation and brake lights only. Start off by checking for 12V on the orange wire at the brake light switch. Key does not have to be on for this test. If good, then depress the brake pedal and test the white wire at the same switch. If it is good, then go to the connector on the steering column. Connect test light to the white wire and push brake pedal. It should have 12V. If not, then it's between the pedal switch and the turn signal switch. If it does have 12V, then test the yellow and the green wires in the same connector with the brake pedal pushed. If the white wire has 12V, but neither the yellow or green do try moving the turn signal lever for left and right. If no change that portion of the T/S switch could be bad. Test the turn signal flasher circuit. With the key "on" test the purple wire in the T/S connector. if there is 12V, then position the turn signal lever for a left turn, check for 12V at the yellow and the light blue wires. if on solid, then move lever to right and test the green and dk blue wires. If either or both come on solid and do not flash, try replacing the flasher and retesting. If the purple has 12v, but nothing else works, you possibly have a bad T/S switch. If they all work there,- the problem is somewhere between there and the tail lights. Check the firewall connector located to the right of the gas pedal and also the connector at the rear frame rail on drivers' side. If you have 12V there on the yellow and green with the brake pedal pushed, your problem is at the tail lights,either a ground issue or bad connectionin the socket.

For the tail lights, check for 12V at the H/L switch with the switch in either park light or headlight position. You'll be testing the 18ga brown wire. If good,but still no lights, check the fuse. If good, then check the connector near the gas pedal, testing both sides on the brown wire for 12V. If good there, move to the rear connector. If the brown wire there has 12V the again, possibly in the tail lights them selves, or a bad ground.

This is a very basic way to describe how to test. I apologize if I left something out, but this should give you an idea where to look . It'll take a little time, but time is cheaper than buying parts you may not need.

Probably the most important thing to check for is grounds. Should have a ground wire (10 ga) from battery (-) to the radiator support. Should also have one, or two from the engine to the firewall. I personally like to ground the battery cable to the frame and the engine. I'd also add a 10 ga ground wire from the rear frame to the rear cross sill of the bed, or ground wires from the tail lights to the frame. You can never over-ground a vehicle! LOL.

From reading your postings, if I understand correctly, this was all working previously? if the vehciel sat for a period of time, even the slightest amount of moisture could corrode a ground connection and cause alot of headaches.

[donthekawguy]

I guess I'll get my tester warmed up for a workout today. lol When I first got the truck I got it home and tried the headlights-nothing. Hit the dimmer switch and they cameon low beam. Hit it again and nothing I do remember that much. I just figured it's an old truck and I was going to rewire it anyway. The other day I did put new radiator supports on. The ones that go on the top of the radiator support that are wedge shaped. I might have bumped something so I will check that first. The reason I think the dimmer switch is bad is the other night I had the lights on and hit the switch and the highs came on and the red indicator light came on the dash. I then switched it to low beam and it went to low beam. When I put on a new headlight switch I pulled the switch and nothing. I hit the dimmer switch and I had low beam. Hit it again and nothing. So it worked the other night and now nothing so it won't hurt my feeling to spend the 12 bucks for a new one even if it has nothing to do with the problem I'm having now. Thanks for the help and I'll post when I get around to doing the testing this afternoon.

[cori 64]

just put a wire from the bed to the frame !!!

[donthekawguy]

Just got the truck back from having the brakes done. I had them install my new wiring harness while they had it up in the air. It has already blown the fuse for the tail lights. I also have no brake lights or low beams. I looked under the dash real good today and found probably 10 splices and the fuse block was all corroded and nasty. I think it's time for a new harness. I found one on the classic truck site that looks good and hopefully will cure all the problems I'm having. The harness looks to be plug and play and shouldn't be too hard to put in. Anyone ever done this on here? Also when I have the cluster out I can rebuild it and make it purdy.

[Rufton]

Combo gremlins always a possibility.
I fixed random tail light issue by running a ground strap from frame to bed as already mentioned; no drilling needed.

[donthekawguy]

Tried the ground wire and nothing changed. Time to get a harness I guess. Ever since I was a teen I have wondered why people cut up harnesses instead of just fixing it right.

[hight3chredneck]

Originally Posted by tincan1966

The dimmer switch has absolutely nothing to do with the tail lights, same as the turn signals. They are all different circuits.

...

cause alot of headaches.

this post helped me so much, my blinkers would work, tail lights worked, but only 1 brake light would light up. tested how you wrote it out here, and found no power to the yellow wire in the steering column. Found out that the little pins underneath the Turn signal had a sub-par connection, and preventing the brake light from lighting.

Thanks again

[tincan1966]

Originally Posted by hight3chredneck

this post helped me so much, my blinkers would work, tail lights worked, but only 1 brake light would light up. tested how you wrote it out here, and found no power to the yellow wire in the steering column. Found out that the little pins underneath the Turn signal had a sub-par connection, and preventing the brake light from lighting.

Thanks again

Glad it helped yoou out.

[Vernski]

Hi Don here is a link that may help you it's for GMC but as we know that they are alike and has some good tips. If you need a wiring diagram you can get one on the forum here, just use the search function and you can download it. Don't forget the ground gremies are to get you..Vernski

http://www.6066gmcguy.org/wire-tips.htm

[donthekawguy]

Thanx Vern but I got it all fixed. I just dove in and replaced all the connectors and grounds. Everything works great now. I just need to wire up the parking lights and blinkers for the front after I figure out the new gas leak I have.

[Don Quixote]

When I first bought my truck a million years ago, I spent months chasing the same problem. Every time I turned my lights on, I'd blow a fuse. I had just about rewired the whole truck and re-grounded it and still no dice.

Turns out it was a front light bulb filament bouncing around and hitting the other filament in an 1157 bulb. I changed the bulb and cursed myself for not checking the simple things first.

[Rufton]

Originally Posted by Don Quixote

When I first bought my truck a million years ago, I spent months chasing the same problem. Every time I turned my lights on, I'd blow a fuse. I had just about rewired the whole truck and re-grounded it and still no dice.

Turns out it was a front light bulb filament bouncing around and hitting the other filament in an 1157 bulb. I changed the bulb and cursed myself for not checking the simple things first.

I'll try to remember that bulb short gremlin. Sounds like a mean one

[AzCountryman]

My tail lights dont light up when I hit the brakes but will light up once I turn the head lights on. Although on they dont respond to me braking. Think this is a bad brake switch?
Day time driving is fun....just turn on the head lights every time I brake...lol