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Not sure If I'll need help with this topic just yet but decided to start this thread / discussion to help me get the mind-set. Maybe this thread can help others who need to sort out the trailer wiring. Ok so when I bought my truck in 2013, it didn't have a bed or body on the back. I basically bought a truck with just a cab. Previous owner was using it as welding rig. He got a new truck and swapped the welding body onto his new truck. Unfortunately he was not so nice and he cut ALL of the wires in the back for the tail light and towing. Left me with the rats nest bunch of cut wires. I used a test light to get the basics connected for the stop, turn and tail lights and a basic 4 pin connector for a small utility trailer. Now I'm getting ready to setup wiring correctly with an aftermarket 7 pin connector. I'm getting ready to do a little more serious towing. I'll be towing a 10,000 lbs dual axle / electric brakes enclosed car trailer from New Jersey to Florida Multiple times this May and June, each trip 2000 miles round trip.. I appreciate the availability of the 2002 FSM from the mopar1973man website and found the wiring - trailer tow diagrams. This will help with identifying the wires based on color codes among the mess of cut wires. This truck has the factory trailer tow package. There is a trailer relay in the PDC. There is a brake controller under the dash which appears to be wired to and connected to the factory harness, plugged above/in front of the brake/clutch pedals. The brake controller appears dead, and upon brief investigating found a blown trailer Jcase fuses in the PDC. (Mine had a 20 amp Jcase in the trailer slot, it should be 40 amp. Also, the stop lamp had a 40amp Jcase it should be 20 amp. I'm guessing the previous guy swapped them for some unknown reason. Also, for some reason the fuse slot numbers in my PDC don't match the fuse numbers in the FSM trailer wiring diagram. Is this a common issue? Wondering if it's a typo in the FSM. Going to try to figure out these cut wires one day this week, hoping for nice weather. For starters I've at least identified the LB (Light blue) electric brake wire among the rats nest. Pictures below starting with the rats nest: The brake controller, factory or dealer installed? MY pdc. Jcase fuses are mixed up. FSM Trailer Tow wiring diagrams:

Today I went to borrow my friends car hauler to rescue my broken down commuter car and only the brake lights and turn signals would work on the trailer. I tried my second 7 pin connector for the 5th wheel in the box and it was the same thing, so I figured the problem is upstream of the 7pin connectors. Did a bit of reading and found the big square 40a fuse in the fuse box in the engine bay and sure enough she was toast. Stole the 40a from the fuel heater until the parts store opens in the morning and everything was working again. I'm looking for some suggestions why this could have happened? I My guess is that it was one of the following things: 1) 19 year old truck and maybe just time for it to go? 2) My 3 year old son likes playing with water guns and could have squirted a bunch of water in the 7 pin connector and shorted something. 3) I have LED reverse lights on my dump trailer and maybe I was in reverse long enough for it to cook the fuse 4) maybe somewhere there is a corroded wire that is creating a lot of resistance If the fuse pops again, where should I look first? After replacing the fuse I drove around with my friends trailer and it was fine. When I got home I hooked up to my dump trailer since I will be working tomorrow and everything worked fine with the new fuse, so I don't think there is a short somewhere since the fuse didn't pop. The only relevant information I can think of is I recently replaced the battery on the dump trailer with a larger capacity deep cycle battery, but I don't see how that would matter. I've had the LED reverse lights on the trailer since I rewired it 1.5 years ago. I don't remember the numbers on them but they aren't a high power light. Maybe if I blow a fuse again I can run a relay with the main power source coming from the dump trailer battery instead of powering straight from the trailer wiring? Any advice would be greatly appreciated! Thanks!