Thanks for the help guys.
Truck is a 2012 GMC Sierra 2500HD. I used a 7 to 4 way adapter I have that has LED's that light up for each channel and it shows power for the marker lights. I also tow another trailer and last time (about a month ago) the marker lights on the trailer worked fine.
When I'm plugged into the camper the brake lights are nice and bright, same with the reverse, and the turns signals work and are also nice and bright, but nothing for the running lights.
I talked to the previous owner last night and he did recently replace the plug to the truck because he had an issue that sounds like a bad ground (wrong lights came on at certain times).
So when I'm checking for a good ground were talking to my truck right, not a grounding plate I haven't found yet on the camper?
Thanks again for all the help!
