Either headlights or running lights, but not both :(

[K85 Octane]

I plugged my headlight switch in for the first time. Re-wired my whole '68 but used the Painless $$$ kit for it. Pretty much plug and play. But now I've got a problem. When I pull the switch out, I get running lights, pull it farther and I get headlights. I don't get both

* Switch is not installed in dash. Does it need to be grounded against the dash?
* I don't have my tail lights installed
* I get running lights. I also get hazard lights. There is a clear difference in brightness. I have not, however, turned both on at the same time.
* This happens with my old switch, worked when last removed. Also works with my new switch.

Truck has been coming together so smooth. I guess something was bound to F*** me.
Any idears?

 

[K85 Octane]

I should mention. The core support has it's own ground. The lamps have ground wires that I added running into the core support. I've got continuity from the parking lamp housing to the negative terminal.

 

[1-ton]

I had this happen to me about 25+ years ago on my 1970 Buick 455 GS Skylark. I vaguely remember the problem was a loose wire terminal going into the light switch plug. Since all your lights do work at some point, then the problem should be at the switch. Try pushing in all your wire terminals from the back of the light switch plug with a small flat blade screw driver, in order to make sure thier in all the way, and making contact with the light switch terminals.

 

[K85 Octane]

I'll try that next time I have time. Thanks

 

[6872xtc]

Is the problem only in the front marker lights? Or all 4 corners? The reason that I ask, is that factory '67 trucks would turn the front marker lights off when the headlights were on. I wonder if there is this possibility in your case. Unfortunately, I never tried to find what the difference was between '67 and '68 in order to make this happen. I have owned both years and I know that it wasn't a mistake, but that is all I can tell you. I can't explain why 2 harnesses would produce the same results.

 

[K85 Octane]

This is a 68, but can't remember if the Painless kit was year specific or just 67-72. Mine has fender reflectors, no lights or wiring for the lights. So, this is the orange lens's in the grille. Currently, the bed is off the truck, so I don't know what the back end it doing.

I want to get to this but am so damn busy with work I can't. Truck sits outside, gets dark when I leave work and it's cold lol. (fiddle playing) So hopefully over the weekend or next week some time.

 

[6872xtc]

Yeah, I understand not wanting to work out in the cold. But at least you already did the fiddle playing for yourself! (Lol!) I am just glad that I don't have single digit temps to deal with this morning!

I wish that I knew what to tell you to check on the switch plug or wherever. And I was just throwing the information about the '67 just in case your truck had something in common with a ' 67. I had a truck once that was titled as a '68, but looked like a '67 in every way, so maybe you got something leftover. But I don't know why 2 harnesses and switches would act the same.

 

[diesel4me]

It could be ground related too--perhaps having no rear lights yet creates a ground loop or something ?..

Maybe this will help,if you can read it...

 

[K85 Octane]

Ok, I've got it. Going to be as thorough as I can for future searches.

It all has to do with the switch and connector going into the switch. It seems to be a 67-68 thing. HOWEVER, even on my brand new wire harness, labeled as 67-72, it was set up for the earlier model.


Check out the pic below.
Terminal A is for 69-72 trucks
Terminal B is for 67-68 trucks

Looking at the plug you'll see that terminal A doesn't have a wire and terminal B does.
Terminal B powers only the front parking lights and looses power once the headlights are turned on. Terminal A is technically only for the front lights BUT is connected to the terminal next to it. So how the flat metal connects the two. That other terminal is for the rear tail lights. These do NOT turn off with the headlights.

 

[K85 Octane]

My new headlight switch has both terminals because it's easier to make one switch for all 67-72. That's my theory anyway. The original switch looks the same as my new one. 69-72 truck switches actually have terminal B missing and have a wire going to terminal A.

All I have to do it pull out the wire from the connector and replace it in the open spot. This should give me power to the parking lights while any light is on.


Here are some more random pictures I came across while searching

 

[K85 Octane]

BTW


How F***ing relieved am I?

lmao

 

[b454rat]

It's in the switch. When I had my '62 I had to replace the head light switch. I racked my brain out trying to figure out why the parking lights wouldn't come on when headlights were on. Come to find out its how the switch is wired.....

 

[6872xtc]

Good deal! Glad that you found this!