trailer light issue: narrowed to where the 5 prong goes in...?

[gride]

my trailer lights and blinkers all work, but when hooked to my truck i have to pull the adapter a little to get it to run the lights. then, my right brake light/blinker doesn't work. how can i check my truck. i've purchased a new 5 prong. happy thanksgiving.

[Rick]

Here is a link to a wiring diagram. http://www.etrailer.com/faq-wiring.aspx . You can check the wires where they come out of the truck but it sounds like a connector issue. Do you have an adapter from the truck to the 5 wire or a 5 wire coming out of the back f the truck? I would try cleaning the contacts with a small rat tail file, if not try the new connector before you cut off the old one.
Good luck.