If the wires go into the axle tube to go cross ways from left to right, that can be a problem over time. The wire insulation becomes brittle and cracks inside the tube causing a short. And the wire vibrating around inside the tube wears off the insulation creating a short.
When I rewiring mine I made sure to "not" use the wires in the axle tube. See this post it may help on how I overcame the problem.
http://www.sunlineclub.com/forums/f6...ade-10711.html
I also did the independent wiring upgrade. If you are doing a total rewire it is something to consider. And use wire large enough. A minimum of a no 10 awg main feed line and then min of a no 12 awg to jump left to right. Since I'm a ways back there I went no 10 right to the wheels on all 4 tires. I now have no problem getting full amperage to the brake coils.
It sounds like your into re-wire project. The only way I know to ring that kind of problem out is using an ohm meter if you have one and start unhooking things to find out where the break in the wire is.
Good luck.
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Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
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