Trailer light plug no power, F-150 super crew with 5.4 V-8 Automatic with trailer towing package

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Jan 7, 2015
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Western North Carolina
My Car
Multiple Mustangs!
Trying to get the old truck ready to go pick up my new car trailer. I knew something was wrong with the trailer lights last time I hooked up the dolly they did not work. I cannot pull the enclosed car trailer without lights and electrical to the brakes.
So what I have done so far. Got the owner's manual out and went to the inside fuse box. All fuses are good inside.
Now I went under hood and there are two 10 amp fuses #19 & #20 labeled in the owner's manual as "Trailer/Camper Adapter (right Stop and right turn lamp). the other #20 is labeled, "Trailer/Camper Adapter (left stop and turn lamp). The fuses are good but no power to either side of the fuse.
I then looked over the relays and any that were labeled anything to do with trailer I swapped out with same type from another plug. Never could get power to the two fuses. Do any of you real mechanics have any suggestions on how those get power? I looked online for wiring diagram that I am totally no good with and found nothing.

My Heat AC has a mind of it's own I can turn off and it turns itself back on in 5 seconds. My radio also turns itself on by itself and changes from AM to FM to Tape to CD by itself. Been doing that for a year or more.

I will search the net for info but no luck so far. I have had an ad out looking for an F-250 with V-10 but no luck. For what little towing I will do I do not want the added expense of a diesel. Might even rent when I go to Penn.. I use to pull car trailer with my 73 Mach 1 on it with a 69 Ford cargo van with 240 six cylinder and had no issue just slower for sure.

Any thoughts from a real mechanic will be appreciated.

I'm not a real mechanic, but you covered everything I would start with, too. I would check all of the fuses under the hood, some feed other things.

I have diagrams for a '10 F150. I subscribe to All Data DIY for 5 or 6 vehicles. They cost $20 per year each or $35 for 7 years. Beats the heck out of buying a set of factory shop manuals. I have boxes of shop manuals that I bought over the years and now are just good for ballast. 

Do it Yourself Automotive Repair Information | ALLDATA DIY

I can also PDF the trailer light diagrams for you.

Hey guess what there was not an issue. I was using a set of the magnetic lights that I use when doing tow dolly. I never thought there was an issue with them so never checked them. When they plugged in the test plug nothing wrong. I got out the lights I was using to test and they were dead. $35.00 later I had no issue, lol. I went home took the lights apart and ground wire broken and another wire also. I soldered back and fixed. So good to go for trailer. I put the brake control on it it also works. Hurray. I just assumed the lights I had were good and they were not. BTW the fuses for the trailer lights do not get power unless the turn signals are on so that is why they were dead.