Hello everyone. First Timer here.
I installed a new trailer wiring harness onto the back of my 2002 F250 Super Duty with 7.3 diesel engine. Unfortunately, I was 180 degrees off on my wiring. When I hooked up to the camper I blew Fuse #115 (Trailer Tow Battery Charge) as it connected directly to the camper ground wire. I replaced the 20amp fuse and all other fuses were good. Currently, I have all the truck wires to the harness isolated and have power to all of them except for the parking lights. All the lights on the truck work fine.


My truck has a interior fuse panel on the driver's side as well as two small black boxes under the hood, near the brake booster. The under-hood boxes had only relays in them. Two relays in one black box, three in the other. The box with three relays had trailer left turn and right turn relays. which worked fine. The third in that box, apparently, is for the A/C clutch, controlled by fuse #10. The other black box (with two relays), apparently, are for 4WD Shift on the fly, controlled by fuse #111. So, no relay for the parking lights.


Next, I pulled the fuse panel out a little and checked continuity from the end of the parking light wire (brown with white stripe) at the back of the truck to the back of the fuse box and found that it was a good wire with no breaks or shorts to ground, however no voltage is showing at the parking light wire when I turn on the parking lights. The harness at the back of the fuse box has several wires going into it. The parking light wire (brown with white stripe) is in the same harness as the back-up light wire (black with green stripe) and the back-up light does have voltage, when I put it in reverse.


I'm not sure what happens inside of the fuse box, ie. how does one fuse run a few wires... is there some kind of circuit board?


I know the easy way would be to run a vampire connector from the truck parking lights, or maybe the license plate light to power the trailer lights, however, I'm just not built that way. Any suggestions?

 

I would double check the fuses/relays under the hood. I know when I installed a brake controller, I found no parking or trailer brake lights working. That's when I checked the list in the truck's manual and found that under the hood are more fuses that need to be added or not all of the lights will work. Not sure if specific one for trailer parking but I can check my manual again later today if you need.

 

No fuses under hood on a 2002. Id double check your fuses. Should be fuse 38 a 20 amp fuse.

 

I always miss that. Oops.

 

Thanks Billybob69,


The trailer wiring harness was a repair. A little rear-end collision broke the plastic housing on the wiring harness, so it was just hanging there. All the trailer lights had worked previously.


My manual says fuse #38 is supposed to control the Trailer Tow parking lamps and back-up lamps. Fuse #38 (located in the interior fuse panel) tests good and the trailer back-up lamps have power, but not parking lights. I also noticed this morning that the ABS lamp on the dash is on. Maybe the ABS light related to my poor wiring job at the trailer harness.


Could I have fried something?


I found the wiring diagram here http://dieselinnovations.com/techfil...ses_wiring.pdf


Page 13-21 shows that there should be relays for the parking lamps and back-up lamps. I can't find those relays.


The parking light wire runs from the back of the truck along the frame to just in front of the fuel tank then branches to the side of the truck and goes in under the floor just below the drivers door. I didn't pull up the threshold, but, using a fox and hound line amplifier, I found the wire at the back of the fuse-box.

 

Edit - I took the truck out and "activated" the anti-lock brakes, and the ABS light went out. Probably came on during all the wiring harness I disconnected trying to trace the parking light wire...