I have a 2005 Durango 5.7 that has no power to the wiring 7 or 4 pin wiring harness i have check every fuse that the book says and the left and right relays work but they are not getting any power. I swapped them with the horn relay and they work. the right relay slot for the trailer tow has no power at all the left has only some in the front of that socket. I have heard that there is a tester you can hook to the 4 or 7 way and it will tell you whats wrong but can't find any one that has it any Ideas thanks Brian