We did the same thing helping a fellow camper running new wires from the front all the way to the back using wire looms. We was hoping to tap into the wiring for the trailer rear lights but couldn't locate the cables under the trailer for those wires. No way was we going to drop the underbelly membrane. We tapped into the junction box where the 7-way trailer cable was wired into the trailer and used the large yellow twist-on connectors for our wiring going to the back.. Everything turned out snug and safe and out of the way.
Roy and Carolyn
I claim Horse Creek Country in Southern Ill - Momabear is from North Texas
We live in King George VA
RETIRED DOD DOAF DON CONTRACTOR Electronics Tech 42YRS
"We're burning daylight" - John Wayne
2008 STARCRAFT 14RT OFF-ROAD POPUP with PD9260C and three 85AH 12VDC batteries
2010 F150 FX4 5.4 GAS with 3.73 gears - Super Cab - Towing Package - 2KW Honda EU2000i Gen
K9PHT (since 1957) 146.52Mhz
"We always have a PLAN B"