IMHO- 1. Take your electrical tester and make a connection diagram of the 6 pin- it will be of great use every time you have to mess with any trailer you're hooking up. The 12V pin will jump to 14V when the truck is running.
2. I have had good luck with an isolator in my RV. They are inexpensive (about $20) and work automatically to prevent your tow vehicle from being drained and leaving you stranded. You have to find the place in your truck wiring harness where the 12V trailer wire connects to the truck battery charging wire and install it just like the solenoid, except you don't have to remember to turn it off when you park.
Building the classics of tomorrow, today!