No wiring diagram

[DDlighttruck]

I have a fuse and relay marked “skirt lights”, they are factory wired and labeled. The circuit is not being used for my skirt lights but don’t focus on that just yet.

Up here we use an aftermarket program called Mitchell for wiring diagrams. I couldn’t locate it on there, so I went to the dealer. They couldn’t find it in any books either, I believe the online diagrams are basically PDFs of the paper books. I asked one other mechanic about it, and he said you won’t find one, because they were an option. I did get a paper copy of the diagrams and couldn’t find it either.

Starting with the basics- pull the relay, using a test light, I have constant power on one terminal. Turn the market light switch to “on”, a second terminal has power. Marker switch off, terminal 2 loses power. Ok, cool. Plug in a relay tester and a relay, turn the switch on. A third terminal now has power. I can hear the click as it does it’s thing.

There’s only four pins on this relay, three have brown (power) and one has white (ground). So I’m pretty sure that’s power in, trigger power to operate the relay, and power out.

Agreed?

So take it a step further, follow the brown wires to the fire wall. There’s a plug on the outside of the firewall. There’s only two brown wires on the inside half, and only one brown wire on the outside half. The one brown wire goes to the factory four wire that feeds the rear junction block for tractor lights.

Put everything back together, pulled the plug apart, got a buddy to help for a minute.

Back to basics- tested the terminals showing brown wires on the inside for power, using the pins on the outside of the firewall with a test light.

I had my buddy pull the fuse in and out while testing, for the skirt light circuit. I could clearly identify with a test light, one pin gaining and loosing power as he removed and inserted the fuse.

Does that sound right? I identified the switch that controls power to the relay, confirmed the relay operates, and traced from the inside of the truck to the outside of the firewall to discover which new colour wire to trace on down from there.

That’s as far as I had time for. There’s more to the story but I’m trying to not (Lol) overcomplicate things in the first post. Part of this is me thinking this through out loud