Any place I should start looking? Pops fuses left and right.

Thanks!

 

I always look first at wiring and components that were added after the truck was built. Trailer wiring is usually a good place to start. If you have a 6 or 7 pin trailer connector on the back, pull it apart and have a look inside. Wires come loose in there, or can sometimes get shorted together by a big ball of mud or slush that builds up in the back of the connector.

 

a trick to help while your disturbing possible fault locations, make a visible test light removing the running light circuit fuse, jump the two terminals with a long wired test light thats visible from where your working, with the running lights on, the shorted circuit will light the test light bulb until you locate the short, then it will go out, like torquefan said, the trailer plug is always suspect, if you added running cab lights, 2nd priority, the wires chafe at the drilled hole over time if not insulated correctly, hope this helps.

 

The only problem with that is you'd have to remove all, or at least most of the bulbs involved first for that to work.

You can do the same thing with a heavier load, like a couple of turn signal lamps, or maybe a headlamp. If there's a short, the test lamp(s) will light full brightness, and the clearance lamps won't light at all. When the short is not there, the test lamp and clearance lamps will light to half brightness.

I agree that the usual culprit is amateur trailer harness wiring. Usually in the connector, or where the harness gets pinched going through the frame or under the spare tire.

hope it helps

 

Since its a first gen we are talking about, dont forget to take a peek at the headlight switch FIRST.... overheated/scorched wiring is what caused my running lights to fail while the brake/headllights/tailights still worked...

IF that is the issue, you may want to place the running lights on a relay while you are in there.. check the stickey for a post on doing that.

 

Thanks guys, All of my wiring is coming apart..... I wired the tool box and headache rack when I was younger and dumber.... I really want to put all that stuff on relays now. I want to put the trailer wiring on relays as well, but I can't find a waterproof box that meets my requirements being that it will be on the bumper.... any other ideas?

 

Army surplus ammo box?

Why a relay? How much load on your add on circuits?

 

Not much, but I would like the trailer wiring to be a little heavier. I pull a 26ft trailer from time to time with a ton of lights on it and none of em are leds.

 

Schram, I beleive it was user BearKiller who posted pics of a box he used when running relays to his trailer harness, it was a year or two ago...
If I recall right, he got his box from an RV dealership or such..
hope that helps..

I ran a relays on the wiring immediately "downstream" from the headlight switch on the running light and taillight circuits, so the entire circuit for the truck and the trailer harness is fed from the relay. the relays themselves are tucked up under the dash.

 

Gotcha. Are the stock wires heavy enough?

 

Yes, once your past the headlight switch itself they are.. use at least a 10g wire from the battery to the relay tho and DONT forget to install an inline fuse from the battery to the relay.. I used 12g wire and wound up replacing it later..
pics are no longer visible in this thread, but the L7 isnt hard to isolate.

https://www.dieseltruckresource.com/...t-t255702.html

 

Trailer Wiring Upgrade

BTW, last weekend I borrowed a trailer that had a broken clearance light. Near dark, it shorted out. Only took out the 10 amp fuse for trailer lights. Truck lights and all other trailer functions remained. Flashers to the barn, no issues.