Jss, I feel your pain. I feel the same way about my interior - ready to just be done with it. If you've got plenty of cash, take it to a good restoration shop and say fix it. But keep your wallet handy. As all have said, it will cost around $500-1000, even a qualified guy just needs time to get it done.
I also agree with those encouraging you to do it yourself. Eat the elephant one bite at a time. If you've already pulled the groups to the right areas you're about half way there. If the wires are well labeled, as most kits are, it's pretty much paint by numbers. Wiring these old trucks is pretty basic - every device needs power coming to it (from the battery via the fuse block) and a place to return the "leftover" juice to the battery (known as a "ground"). I had a spare battery with a good charge and used it with short leads and alligator clips (available at Radio Shacks etc) to test everything before I wired it in so I knew it worked properly.
As long as each device is well grounded (bare metal, well cleaned, screwed down tight) and the whole chassis is interconnected with grounding straps (cab to frame, bed to frame, frame to battery or engine block, engine block to battery) all should go well.
Think of electrical power as water in a hose, and the battery is the main valve or faucet. The pressure is "voltage" and the rate of flow going through the hose is "amperage". Most everything needs the same amount of pressure (volts) in order to work properly. Devices needing more power need more flow (amps) and have higher rated fuses for that circuit, and usually heavier gauge wires (smaller number gauge means thicker wire, don't ask). All the water has to go from the battery (think of it as a water tank under pressure) to the fuse block (just like a manifold) where it is redirected to each branch circuit. From there the water flows to the device needing water pressure (electrical voltage), sometimes having to travel through a switch (just like another valve) on it's way to the device. When the device is through with the pressure it sends all the water back to the battery to be "recycled" and repressurized by the pump known as the alternator. Some circuits are "hot" and always on regardless of key position while others are "switched" and only on when the key is on. For the most part, your fuse block and instructions will take care of this distinction but it's good to know.
Pick a simple circuit (like the engine area, few switches, straightforward) and see if you can't get it working (success here would be starting the engine) and I'll bet you gain confidence and learn a few things, ready to try the next branch circuit. Plenty of people here able and willing to help you with any bumps along the way. Just remember to keep bare ends protected (12 volts DC may not as dangerous as house wiring but it can bite the heck out of you) and taped until connected and test, test, test.
(PS - any electrical engineers out there please save the critiques of my perhaps imperfect analogies, just trying to give a big picture overview to the guy)
As for your questions, the lights appear to be using the housing as the ground connection. Use the test leads I mentioned, one from the battery positive to one of the wires, one lead from the battery ground to the taillight housing. Repeat for the other wire. The brighter of the 2 is of course your brake/turn light, the dimmer your taillight. the wire labeled turn signal will carry the brake light current and switching is handled through your turn signal switch, just connect as labeled. The third brake light is optional if you want to add one.
If no reverse light wire exists in the harness, find a switched circuit (like your radio, or fuel pump wire) and run that to your reverse light switch (I have to add one to mine) then out of that and to both reverse light housings. The light housing is again acting as the connection to the body and ground.
Wires can be connected using zip ties (use black, not white) or nylon clamps found at your local auto parts store.
Last edited by The Green Farmer; 08/27/2011 4:48 AM.
