Only front parking lights work. Need help.

[White70C20]

I replaced the headlights. I can check for power coming out of the plugs. I can also replace the dimmer switch.

[Jurassic-1]

Be sure to also check the ground wire from the headlamp to radiator support.

[White70C20]

Thanks! I just got done cleaning those ground connections.

[White70C20]

Ok, I just checked both headlight plugs and the grounds. All are good. The test light lights up very bright on the grounds and all 3 prongs of the passenger side plug. It lights up bright on one prong of the drivers side plug. Not sure what to do next.

[Jurassic-1]

It should only light on 2 prongs 1 is a ground. I would check to see if the brown wire is on top and the green is facing the middle and the black ground is on the outer prong. It sounds like there is still a bad ground. If you have power on the 2 colored wires it means the brights should be on. if you take a short wire while the lights are on you should be able to put it in the black wire at the plug and ground it somewhere clean and it should light up. If it does you still do not have a good ground. The other side may have a bad connection but start with the one tat has power.

[White70C20]

Ok, cool!
Thanks!

[White70C20]

Also, I noticed today that there is a couple of wires coming up from the back of the engine that aren't going to anything. I thought maybe they were for an electric choke, but this is the original carburetor.
Any ideas? Probably not anything related to the lighting problem, but I thought I'd ask.

[Jurassic-1]

Did the truck have AC? It could also be for the transmission. Some had a solenoid hooked behind the carb that would work off of a temp sensor. I am not too sure how it worked. What color are those wires?

[White70C20]

The truck is pretty basic. No A/C. It's a manual transmission. The wires are black. I don't know if that's what they always were, or if they're covered in oil/grease.

[Jurassic-1]

At this point I think it is a ground problem. Try to ground the black wire at the plug and with a piece of wire ground it somewhere you know is clean and see if it lights. if it does recheck the area it is grounded and see if they look clean. There are multiple ground wires on some grounds which could promote corrosion.

[Jurassic-1]

About the wires in the photo. I looked on some diagrams and did not see anything like this. I would try to follow them to the starting point. They probably do not have power to them but if they are not needed you could either wrap them and tuck them away or shorten them and cap them. I would not leave any wires unprotected in case of a short.

[White70C20]

Ok. Thanks!

[White70C20]

I ended up taking the truck to a mechanic we know this evening. He's hopefully going to look at it this week.
Thanks for all the suggestions and ideas.