So someone told me my tail lights arent working so I checked found the small 15 amp fuse blown under (small ext) number 15 so i replaced it started the truck up and it popped as soon as the lights were turned on. So I removed all the bulbs to the rear including tag lights put another fuse in same thing. The brake lights still work and everything else is fine. Wires all look good no corrosion or anything. I'm totally lost at this point anyone have any ideas what else to check? Is there a relay for the tail lights?

 

I havent checked in the manual if could be this but there's a connection box for trailer (if you have) where the spare tire is, wires join there.

 

Two fuse boxes under the hood and another under the dash. Buy new bulbs and if that’s no good get new sockets.

 

20 Amp fuse. Location 27

 

I had the same issue. Come to find out my third brake light "little center one on the wing" had such a small spot of corrosion and it was moist. It shut my whole tail light section down. I cleaned all the tail light pigtails checked for moisture and replaced all the bulbs. I hope this helps.
If the fuse is still popping something is touching or wet back there. Take your time it's tedious.