Originally Posted by robertel
I don't know how to tell which wires at the plug are the correct 2.
Do these wires exit the tongue beneath the belly pan. On mine the very front section of belly pan sits on top of the frame with no rivets accessible? Does this make sense?
Unless there is another one, my 12v
fuse panel is under my sink, front of center of trailer.
If the break away switch wires are broken, for me there's no reason to follow them. To me, it's a replacement issue. The break away switch is easy to see, the power tongue jack is easy to see, and the 7 way plug is easy to see. To replace the break away switch and the jack power wire, I'd just find them in the 7-way plug connection point and replace them.
My trailer is a 1976 31' center bath. There are two pairs of wires going toward the street side. One pair is cased to remind me of romex. Those two are the brakes. That's easy to test. The other two are single wires and those are the jack/break away switch. I removed the inside front panel so I could get at everything up there.
My Service manual shows a fuse panel at the 7-way location under the fiberglass cover. The previous owner of my trailer removed the fuse block and disconnected the break away switch. He pushed the break away switch wires back behind the panel with wire nuts attached to each end. He hot wired the jack by cutting into the umbilical wire and tapping into the 12 volt
line and taped it all back up.
I used this drawing as my plan and everything matched a standard 7-way tow vehicle plug and everything works as it should.
I used a multi meter, a bright 12 volt
jumper light, a 7-way tester, and a small 1 amp battery charger. My tow vehicles were not involved in my testing and rewiring the trailer. I did it all with the meter, the light, the tester, and the charger. I installed a new break away switch, installed a new fuse block, rewired the 7-way trailer plug, and installed a new molded end umbilical wire. My exterior lights were not working correctly, so I replaced all the clearance/running lights with LED fixtures, installed all new bulbs, and installed all new tail light lenses.
I twisted, soldered, and seat shrunk all the connections except the one cord end I put on and the small wire trailer plug connections. The big wires, I stripped and soldered. I soldered all the ground wires together by fluxing them and soldering them with my map gas torch. The main ground wire is bolted to the frame of the coach.
Important: I ignored the color of wires and mapped the functions. The colors of my wires didn't match the AS service manual or the plug plan.