99 E450 super duty 7.3 Cube van 15ft

I just wired up the 7 pin connector to pull my dump trailer. The wiring for the back lights go through the truck body. Under the back of the truck on the cross member is two plugs conectors, one for the electric brake and one for the lights. I tried to get the wire harness from ford but for $84 buck I got the wire connector to plug in with wires coming out to splice into. So I gave it back and just cut the ends off and spliced in the wires. All lights are typical brown, green, yellow, white, blue (elec brake), While I just figured that they were live and connected them in. Well when I hooked up today to the trailer, electric brake works but no lights. Are those wires live to the fuse box or is there another fuse that is not plugged in for them. I don’t have the owners manual to see what the fuse box diagram is for the fuses.
Any idea’s

Thanks
Rick Sweares

 

I believe there is a special Fuse box under the hood for the R/V package.

 

Yes, there may be some fuses and or relays missing or disconnected up front for the trailer harness. I guess they didn't want the wires to be "live" unless they were going to be used.

 

I was able to download the manual for the truck I found it on a ford web site. Looking at the fuse diagram, you are right, the fuse box under the hood has all the fuses, and relays it suppose to have. As was mentioned I have the eclectic brake, the battery to the trailer, just no lights. Seems like I have to do what I didn’t want to do, Check all connections in the splice where I cut the plug off. Check to see if I get any thing there, if not start tracing. Worst comes to worst I will splice into the wiring inside the box and drill a hole in the floors and run the wires to the plug. Kind of stinks it don’t work. Maybe someone screwed up at the factory of when they attached the box to the frame. Something’s unplugged somewhere; I looked everywhere under the dash and under the hood.
Thanks so much for all the help, if anyone can think of something just let me know

heres the link I got the ford manual. Other sites wanted $25 - $45. They also have the added one for the Power stroke.
It just stinks when you buy a used truck and the old owners eats them or loses them.

https://www.fleet.ford.com/maintenan...ks/default.asp

Rick



Rick Sweares

 

Well I got some time today to check things out. Well it seems when the truck had the body put on. (this is a cube van) they spliced into the wire harness on the rail, well rather they cut the wires and ran them up through the body of the cube van. The lights are molded into the box. So the plug in the back on the frame was just dead. So I spliced them all together and everything works fine.


I’m just a little troubled??? In the cab of the truck is the fuse box under the dash, which has fuses for the running lights and brake and directional. Under the hood has the aux box with relays and fuses for running lights, brake, signals etc. You would think I would have had 2 sets of wires for these two fuse boxes. One set for the vehicle lights… and one set for the tow package wire harness in the frame. What is the purpose for the 2 boxes???

So all in all, Things should work good.

Now time to work on getting my gauges and installing them

Thanks for all your help.... This is a great Forum.... see ya around

Rick Sweares
Worcester MA