Wiring quandry for back up lights

[Team Stratos]

I installed some LED back-up lights on my trailer about 3 yrs ago. Just pig tailed off the stock backup lights on the trailer. After about 6 months I started having a problem where about half the time when backing the trailer into the lake my fuse would blow for the trailer back up lamps. I was unable to isolate the cause so I just started unplugging my trailer wire harness when I had backed to the waters edge. Well now my fuse is blowing when I go to back into the garage. No water involved. I am showing continuity between ground and the back up lead on the trailer harness. I first disconnected all backup lamps and still show continuity. Trying to isolate I cut the lead to the starboard side backup light with no change.. Then the backup solenoid lead to the trailer, no change. Last, I cut the lead to the Port side backup lights and continuity was finally broken . Before I start back wiring this together, does any body have a suggestion how to solve my dilemma other than run a new+ lead from the harness to the back port side of the trailer?

[CatFan]

Take a look at the wires where the enter and leave the frame. If you don’t find any worn insulation, then check the light fixture itself. Hook the bad wire back up, verify the short is back, then remove the light from the circuit. If removing the light doesn’t fix it, tape a new wire to the old one and pull it into place.

[mikesxpress]

Check continuity from your backup 12Vdc + wire to ground. It sounds like the wire is rubbed thru as noted above.

[Team Stratos]

I wound up pulling a new wire on both sides of the trailer and wired into the trailer plug. When I attached the reverse wire from the solenoid I again have continuity on my meter. Should the solenoid have continuity? I guess my next step will be to hook up the trailer to the truck and see if the solenoid pops the fuse by itself and then attach lights one by one.

[CatFan]

I wound up pulling a new wire on both sides of the trailer and wired into the trailer plug. When I attached the reverse wire from the solenoid I again have continuity on my meter. Should the solenoid have continuity? I guess my next step will be to hook up the trailer to the truck and see if the solenoid pops the fuse by itself and then attach lights one by one.

If by continuity you mean a meter beeps indicating a connection, that won’t work with solenoids and incandescent bulbs. Both of those things are just wires connecting 12V and ground, so they will show fairly low resistance to ground when the are wired properly.

[Team Stratos]

CatFan, That's what I was thinking but wasn't 100% sure. I tried it with just the solenoid hooked up and she's working fine. Now I'll start hooking up the backup lights one by one. Thanks for all the info.

[billnorman1]

Lights and the solenoid will both show continuity to ground. Incandescent lights are almost a direct short, until the filament heats up and the resistance goes high. The soenoid is a coil of wire I wouldn't expect more than 10 Ohms but it could go higher.