Trailer wiring ground?

[TWilkening]

Does anyone know where the ground in the trailer wring attaches to the frame? I'm having some strange wiring problems and ground seems like a logical cause. Thanks

 

[WDixon27]

typically anywhere it can get a good clean connection will work, they sometimes get a little help through the hitch which can make a bad ground weird to track as it makes connection at the hitch ball

 

[TWilkening]

I found my problem. I had 2 wires switched around in the plug.