electrical wiring

Hello all,

I'm new here as my father in law just gave us a small bonair tent trailer. I am working on getting the model to provide, but I am hoping you can help me out.

The trailer has a 6 or 7 pin harness, and my suv has a 4 pin. instead of using an adapter, I would like to wire in a new connector. Does anyone know what each wire is for? I have done some research on the internet, and it seems like blue is breaks, but there are no breaks on this (i think).

the weird thing is that I see there is a yellow and red spliced together....

Any help would be appreciated. I may just back my suv up to the trailer and try each one out and see what it does.

thanks,
Dave