I've recently had trailer light issues on my 07 single axle ranger trail trailer. The problem is when I hook my boat lights up which is a five wire flat to my truck which is a seven round to a five flat the blinkers are opposite and I have no running lights( tail lights included ) but my brake lights work. Is this a ground issue? I've used my round seven to a seven which was on my travel trailer and it worked fine! I also hooked my dad's truck up using the same method with the same result. I've searched these forums and haven't been able to find any info. Any suggestions would help me a ton, thanks in advance!

The white wire on the five flat which is the ground wire I believe, I'm no electrician mind you has a melted spot on it so I went and bought a five wire flat to replace it!

Trailer flat wire which has seven wires


New five wire flat with five wires, now I'm lost!

If you want to see if its the ground..run a single ground wire from trailer to pickup....

Ok, where would I hook up the ground on the truck/trailer?

On your new plug white is ground , brown is running lights, yellow is left, green is right the blue is reverse kick out for brakes

you can just strip and touch the ends to the bumper bolts and wrap around the safety chain ?

just clean a spot on both frames and drill a hole , put a flat connector on wire and screw them
down..you could just use alligator clips if you can clean a spot good enough..

Ok so to hook up the new five flat how do I go from seven wires to five wires or can I even do that? BTW thanks for all the replies!

I went to Walmart and for around $40 and bought a converter plug that goes into your big RV pug and has a pug for the small round plug and the flat one. Works great.

This, but you can do it for a far cry less than $40.

from the pic it looks like you have 2 brown (1 runs each side down the trailer) hook both into brown, then it looks like the 2 reds are brake don't know why 2 ? but the bottem pin is brake kick out when you go into reverse . so put both reds to the blue wire. as said above go ahead and put a ring on the white and screw it to the tongue so you get a good ground and report back .

The original 7 wire plug is for a trailer with electric brakes.

Connect old greens to new green, old yellows to new yellow, old reds to new blue, and white to frame of trailer.

Wow after rereading what said, I screwed that up. Connect the solid green on trailer to solid green on new pug, do the same for yellow. The green wire with a stripe is for tail light, likewise for yellow with a stripe. Connect striped wires to brown on new plug. Reds still go to new blue.

Thanks for all the advice guys. I got called in to work so my next day off will be Monday, that's when i will do some experimenting. I will report when I find out what the problem is!