You are correct Mapguy, I no longer have my 2006 and was going from memory on the fuse size. Regardless, if he doesn't have a fuse in that location, it will not charge the batteries. Have found several people that didn't know that.
I was reading the manual on my new truck and it says to improve charging, one can turn the truck lights on.
Left my old truck and trailer at a axle shop to have the axles aligned for a few days. Cable was hooked up during that time and drained the truck batteries. Required a jump start.