Bare bones wiring for a 36' truck

[banjoQ]

First I will admit that electricity is not my strong suit. But I can usually figure things out through trial and error. This one has me stumped which translates to " I can't see the elephant". A little history first. I am working on an un-restored 36' truck that has had many hands into it over the years. The wiring harness is in rough shape, it's a hand made job done with one spool of wire and a bunch of connectors. The truck runs great now and the gauges in the dash work. I am having no success with the lighting, so I have decided to re-wire these separately. I just don't have money in the budget for a new harness. To make this easier, I installed a new fuse block, powered off the batt. with 10 ga. wire. I ran a new circuit to the back for a brake light using 12 ga. wire- replacing the sender switch (truck fitted with juice brakes). This was grounded to the frame and it works. Replaced that headlights and wired them with 10 ga. and tested off of the fuse block, they work. Lights had been controlled by a variable rheosat in the dash, this was a rusted mess. Replaced with a double throw toggle switch, using one side. Wired the switch in and cannot get the headlights to work. I used a VOM to go through the circuit, checking for current. Circuit goes from batt., to fuse block, to switch., testing positive all the way. I believe the headlights have a good ground as they worked off of the fuse block. Any ideas what I might be missing here?

[Teltruck]

Seems there is a trouble in the way the switch is wired. Use a jumper wire to jump the switch terminals to test? Good luck. Make sure you use a fuse in the lighting circuit for proper protection!!
Get a New Wiring Harness as soon as you can! Good luck!

Bob

[41ford1]

If you disconnect the switch and touch the wires together will the headlights come on? A double pole double throw switch usually is powered in at the center terminal. The switched loads are usually on the end terminals. You could run high and low beams off the switch. You might have the switch wired to the out/load terminals. This is just a guess.

[banjoQ]

Rigged a jumper across the switch, and they worked. Problem must be in the switch. 41'- your description of the double throw switch is spot on. This one has six pins, 2-2-2. Tried all combinations of either side and nothing. I guess the switch is one big short, made in China! Back to the supply store and try again with another, made in USA hopefully. Baby steps forward- Thanks.Q

[Don Rogers]

Before you buy another switch try wiring the switch as shown in the diagram below. Use only one side of the switch. See if that works.

[Pete]

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Originally Posted by Don Rogers

Before you buy another switch try wiring the switch as shown in the diagram below. Use only one side of the switch. See if that works.

Some special application switches are setup with the "common" on the end instead of in the middle as normal.

[banjoQ]

Thanks Don for the diagram, but I had it right from the start. Turns out the switch was bad. Lucky for me the shop is only a few miles away. Took my VOM and checked it before I walked back out the door. Came home and wired it up, it's all good. Now, rear running lights. Thanks to all, sometimes those elephants are hard to see.

[Teltruck]

BanjoQ
Glad you solved the problem. You seem to be doing a good job on getting the bugs out. Keep up the good work.
Bob
"Remember "The current that flows through an electrical circuit is directionally proportional to the applied voltage and adversely effected by the resistance"
Bob

[Clem Clement]

Be sure you have a good ground. Our old Fords lose ground when they leave the factory doors

[banjoQ]

Clem- Your not kidding. Although my truck was kept in a garage for fifty years, it saw a hard life. Over the last year of working on this truck I have learned so much. My skills in freeing up old rusty nuts and bolts, finding wiring problems, carbs and the like have improved greatly. Grounds are now the first thing I look for when I have an electrical problem. But it's been fun, almost as much fun as driving it.