Looking for some help with an odd problem with trailer lights (and battery). Recently I was at the lake, put my boat in the water and left the trailer hooked to my truck. About 8 hours later the truck battery was completely dead (was less than a month old new battery from dealer).

Once I jumped the battery I did not realize until the next day that my trailer parking lights did not work. Trailer brake lights and all truck lights are fine.

Took it to a local mechanic and they couldn't find the problem. No fuses bad. Before I take it to the dealer, any ideas?

2013 F150 XLT Supercrew 5.0. All stock.

Any help is appreciated.

 

I'd check the trailer hooked up to a different vehicle before taking your truck to the dealer.

 

Sorry should have mentioned that I have tried 3 different trailers and all have the same result. Thanks for the quick reply.

 

I would double check all the fuses, ck. owners manual for trailer running
light fuse there are 2 fuse boxes in your truck. shouldn't take a mechanic
to check them. if they are okay, I would look in the wire connector for water.

 

Check Fuse F67 20amp in Battery Junction Box under hood. It for trailer parking lamp only. Truck parking lights are different fuse.
No clue why battery was dead. Shifter not in park, interior lamp left on?