I have 68 F600 that is giving me fits with regards to the turn signal and brake lights. I have "Key on' power to the brake switch after using contact cleaner on the turn signal switch below the steering wheel? I thought that it be hot all the time? I know someone has messed with the wiring in the truck. I found a melted wire in the harness and am tracing all the wires. What is the path of power for turn signals and brake lights? I have 1 wire that is hot comin g into the steering wheel. It is yellow and goes to one of the springl loaded plungers there. My flaher circut has been tapped into to power a add on horn switch. I beleive the plunger inthe column is for horn? Not sure whats going on here? I traced the flasher "Hot" wire to a plug that has 2 female and 1 male connector. The male goes throught he firewall to the fuseable link. 1 femlae is the flasher the other is running lights. this plug is not connected to anything. when I jumper the flasher I haev turn signals, when I jumper the other I get running lights. Not sure if this is unplugged or just someone's hack job.

I read that if you add halegon lights they shoud be run through a relay. Well my truck has them and I want to add a relay and eliminate the possiblity of this causing me problems. Can anyone provide the info on how to add this relay?

 

Get those add on wires running to their own power source with a fuse (either key or
always powered) and replace any visibly burnt wires and check the resistance on the
rest of the wires since a bad spot under the insulation could have happened after
all these years. Check all the gorunds under the dash and on the frame front to rear!!
Running the lights on a relay is really a simple circuit, Basically run the relay wiring
all under the hood, a fused wire from the battery to the relay(always on terminal)
then one wire goes to ground, you can tap into the wire that comes from the head
light switch and put that onto the relay(switch terminal) then go to the head lights
from the relay(switched terminal) Do the same for the highbeams and you could also
do a relay for the running lights to take the load off the switch itself. If you need a
better explanation or diagram on the wiring just ask it really isn't too hard and I
always over estimate the load and skycraft has a 80amp relay for the same price as
a 30 amp at most places and you may as well it. use .http://www.skycraftsurplus.com/index...S&Category=207

 

A diagram of the relay wiring would be big help. I did just get a schematic for my truck. When I saw house hold wire nuts used on the wiring I knew that someone else had mickey moused the wiring. I have found burnt wires, cut insulaton hot wires going no where. I am trying to eliminate all the issues. I can jumper to make turn and brake lights work, now I have NO front running lights? I know my fuse panel has some rust. Just can't figure out why the fusible link goes to a plug that plugs into nothing? The mating part might have been removed?

 

I would not worry about the relay for the halogen lights. I have run halogens on all my old vehicles with no problems. You can add a relay, but it sounds like you have bigger problems to fix first.

The brake switch on the pedal should have a hot all the time wire running to it. The flasher should have key on power running to it. On the other side of both the brake switch and the flasher should be wires that run up into the column to the turnsignal switch.

The turnsignal switch takes the flasher signal and the brake signal, and mixes them together to run to the rear lights, since the filament in the rear for the brake wire, is also the turnsignal filament. The other section of the turnsignal switch is a simple switch that puts the flasher on the correct front turn bulb, and also goes up in the dash to the little green turn indicators.

The running lights are a simple one wire circuit that comes from the headlight switch. There is several sections to the headlight switch, and the headlights are powered by a different power source than the running lights. The headlight switch is fed by a wire from the running light fuse, and leaves on a darkbrown wire. This darkbrown wire goes all over the truck to feed the running lights.