Wiring/Lights Help!

[wancosc356]

Hey guys. So I got the truck pretty much ready to go to the dmv to register and title it today. But, I just found out that none of my tail lights are working. My head lights and front turn signal lights work fine. Just curious what could be causing the problem. My wiring has been messed with I'm sure. So a diagram would be great. It is a 1967 short stepper with a 292 6cyl. and 4 speed trans. Non a/c. Any help would be greatly appreciated. Thanks
Michael

PS: I tried to search for a diagram but came up empty handed. I did however see that I should check my grounds, connections and fuses. Im gonna do that now.

[mr48chev]

Here is a link to the diagram that I have on my photobucket page
http://s173.photobucket.com/albums/w...14-2141-56.jpg
In case this one doesn't show up.


On this I'd say the first thing you need is a good test light and test the circuits where the plug goes through the rear crossmember On the drivers side.

That is the connector that is shown on the bottom of the diagram.

If you had the bed off or were working on that area make sure it is plugged in.

Unplug the connector and check the circuits with the test light on the connectors of the plug in the crossmember. That way you will know that you have power to that point and you can work your way through the rear harness.

The color coding will be the same on the stepside but you may not have the side marker lights.

Yellow= left turn/stop
Dk green = right turn/stop
Brown= tail
lt green= backup

Also remember that these have ground wires that have to be hooked up.

[cdowns]

run a good ground wire from one of the bed sills to the frame

[wancosc356]

Thanks for the diagram. I found a white wire that ran from the alternator to something mounted on the rad. support cut in half. I repaired that. I also re covered the alternator ground wire due to it somehow melting its coating off. I doubt that all had anything to do with my tail lights but who knows. I also found some wires after the rear connection that were cut. I spliced them back together the best that I thought was right. The colors after the rear connector are spliced with different colors and dont really correspond to anything. But I now have hazard lights. Both rear lights flash when I hit the turn signal up or down. Still no brake lights or running lights. The connector seems fine. I guess Im gonna go get a test light tomorrow. Thanks for all the info. guys.

[fixit-p]

Thats good news that your right and left turn works because the brake lights share the same wires to the rear check the fuse labeled TAIL STOP then check your brake lights first if all is good check your taillights if it pops the fuse check the brown wire for a short to ground.

Edit==I just re-read your post do both lights flash at the same time?

[wancosc356]

Yes. Both lights flash at the same time. I believe my turn signal switch needs repair also. It doesnt actually click into place on either side and you have to hold it onto the right to get the front signal to keep flashing. On another note, do these trucks have a hazard light switch?

Anyways, I pulled the rear harness and lights and I am going to rebuild them tomorrow with fresh wires. Hopefully that will work.

Also, could anyone point me in the direction or post a picture of the 67 factory fuse block/plate? Mine is pretty worn out and I cant see what each fuse is for and what size it says. Thanks.

[fixit-p]

Ok thats what I thought after I made my post I re-read yours and totally mis read it here's a pick of the fuse block http://67-72chevytrucks.com/vboard/s...d.php?t=121515 at the top of the electrical section longhorn man did a great job putting together a faq section thats full of good info including wiring diagrams which would help you rewire the tailights. As far as hazards go I know my 65 doesn't have them and my 69 does there would be a seperate hazard sw on the column also your fuse block would probably have two flashers.

[cdowns]

an altenator ground wire that melts is usually a sign of a poor ground connection covering it up accomplishes absoulty nothing . that wire is NOOO good it must be replaced with the proper gauge replacement wire and connections both at the alt and motor/frame be cleaned to assure a proper path for the electricity to travel

[wancosc356]

Originally Posted by fixit-p

Ok thats what I thought after I made my post I re-read yours and totally mis read it here's a pick of the fuse block http://67-72chevytrucks.com/vboard/s...d.php?t=121515 at the top of the electrical section longhorn man did a great job putting together a faq section thats full of good info including wiring diagrams which would help you rewire the tailights. As far as hazards go I know my 65 doesn't have them and my 69 does there would be a seperate hazard sw on the column also your fuse block would probably have two flashers.

Thanks for the fuse block link. Im sure I will use that thread a lot. Thanks again.

Originally Posted by cdowns

an altenator ground wire that melts is usually a sign of a poor ground connection covering it up accomplishes absoulty nothing . that wire is NOOO good it must be replaced with the proper gauge replacement wire and connections both at the alt and motor/frame be cleaned to assure a proper path for the electricity to travel

I will be sure to pick up some wire for that ground wire today. Could u recommend the proper gauge? Thanks.

[cdowns]

i'd go at least 6ga

[Longhorn Man]

fixit... thanks for the props man.

[wancosc356]

Originally Posted by cdowns

i'd go at least 6ga

Ok. Thanks

Originally Posted by Longhorn Man

fixit... thanks for the props man.

Still haven't fixed it. Im gonna pull the entire harness from the firewall back and check it out. Thanks for the thread.

[wancosc356]

Ok. Well here is am, still without tail lights. The fuse box pic is a little different than mine but it gives me the general idea.
I pulled the entire tail light harness from the firewall back. The middle harness had a crap job done in the middle and one wire disconnected. So I repaired that section. Then the rear harness also had some crap job work on it too. I fixed that also. I checked all my fuses and they are good. I also checked my plug that plugs into what I think to be a brake pedal sensor. And I started her up. I still have no tail lights or brake lights. I do however have a left rear turn signal light. I know that the turn signal switch in my column needs to be replaced due to being worn out but it still works for the front.

So....I know I am getting power to one rear tail light and I know that my harness is good from the firewall back. Where do I go from here? Thanks

[Longhorn Man]

I posted that to member fixit-p in post #7 where he commented on the FAQ links I posted in this forum.
You need to troubleshoot your problems one at a time.
Start with your tail lights. That's the brown wire. Check for power at the firewall where the harness plugs in, then at the rear cross member in front of the rear bumper, then check the wires going to the plugs in the tail light assembly. If you have power all theway back there, then you need to clean/repair your grounds.
As for your turn signal and brake light problems, if you know 100% for a fact that your turn signal switch is bad, then replace it. That one piece will stop your turn signals from working (obviously) and also it'll keep your brake lights from working.

[wancosc356]

Oh....and the left rear turn signal only flashes with the head lights on.

[wancosc356]

Originally Posted by Longhorn Man

I posted that to member fixit-p in post #7 where he commented on the FAQ links I posted in this forum.
You need to troubleshoot your problems one at a time.
Start with your tail lights. That's the brown wire. Check for power at the firewall where the harness plugs in, then at the rear cross member in front of the rear bumper, then check the wires going to the plugs in the tail light assembly. If you have power all theway back there, then you need to clean/repair your grounds.
As for your turn signal and brake light problems, if you know 100% for a fact that your turn signal switch is bad, then replace it. That one piece will stop your turn signals from working (obviously) and also it'll keep your brake lights from working.

Oh ok. I will do that. I know that the turn signal switch does work. But when u switch it for left turn, you have to lift up to get it to stop. And when you switch it for right turn, you have to hold it to make it stay flashing. But it works to flash the front signals. Where are my grounds? One at the battery to the fender? One at the alternator to the radiator support? And? Thanks

[wancosc356]

Update:

I mounted the tail lights back onto the truck. I now have tail lights when the head lights are on. I still have no brake lights and only the left turn signal light. I pulled the steering wheel and the turn signal switch assembly. It is shot. And one of the wires is exposed under it. I just so happen to have another column with a good signal switch. I just gotta get it cleaned up and put it in there. I hope this fixes my signal and brake light problem. Oh, I do have power in and out at the brake pedal switch. Anyways, just wanted to update. Thanks for everyones help.

[Longhorn Man]

the tail lights ground where the assembly bolts to the bed. Paint or corrosion between the assembly and the bed can hinder the ground. A small strap should be on the drivers side frame rail to bed rail up towards the front of the bed. If you have a steel bed floor it isn't all that important... a wooden (or missing) floor makes it very important. You can make one out of wire and crimp on eyelets.
To do a quick test on that turn signal switch, just lay the replacement column on the floor and plug in the turn signal switch and see what happens out back with the lights.

[wancosc356]

OK!!!! Finally. I have tail lights. There was a red wire that was cut under the dash. And also, I swapped one of the green rear harness wires and have a right turn signal. All systems go....almost. Everything is working except, the reverse lights, hazard switch, and my horn. Im not to worried about the hazard lights right now or the reverse lights. I would like to horn to be working again though. Im gonna do a search now and see if I can find how it should all go back together. Maybe I reinstalled it incorrectly. Regardless, my wiring issues with the lights are pretty much done. Thank you all for your help.

[fixit-p]

Originally Posted by Longhorn Man

fixit... thanks for the props man.

No thank you for putting that together I think having info like that at the top makes the section that much better