I have a 2011 F350 towing a 5th wheel trailer. I have no power to the 12 volt terminal of the 7 prong plug in the truck. the 25 amp fuse at terminal 90 is good and I have replaced the relay at terminal 102. Both were designated for this plug. I still have no power to the terminal at the truck receptical. Checks for power we're done with the truck running. Where else do I need to check?