Mine Is a 97 with 6? 7? pin socket the round one w/ trailer brakes i blew every thing in the truck side plug except for the trailer brake hot (dont ask long story) my blown fuse was a 20 amp located in a small fuse box under the hood driver side firewall side behind the main under hood fuse box in mine there are three fuse boxes all factory the big one then two smaller ones tucked behind the small ones were wrapped in tape i tested all other fuses and relays i could find including the ones under the dash all are fine the turn and park lights to the socket now work but the brake light does not i am now looking for a fusible link looking for other fuse boxes under the hood some are small and hard to find
good luck to both of us
thanks
John

 

On my 97 f150 the big fuse box has one easy latch on the lower front driver side of the box - the lid just swivels up the other two are similar the latches are almost underneath the driver side of one and towards the front of the other you cant really see them but when you find them they arent to hard to get off the 2 smaller lids come all the way off
Thanks
John

 

I know that this is an old thread.. On a related note, when I connect and plug in my enclosed trailer to my '01 SCREW I seem to have to have the running lights on the get my trailer interior lights to work. When I tow with my '07 Silverado, the trailer interior lights work with out running lights or key on.. So... when it's dark out and need something quick out of the trailer, when I have my Ford I unlock the truck, turn on the running lights, unlock the trailer, turn on the interior lights, get what i need, and then retrace my steps to turn everything off. If I have the Chevy I don't have to go to the truck, just open the trailer, turn on the lights... What's the difference in the wiring?

 

The difference is Ford uses relays for the trailer wiring GM wires them hot all the time. If you leave you trailer plugged into a GM the trailer can run the truck battery down and leave you stranded a Ford won't do that.

 

I have a f150 97 5.4 and my pigtail doesn't work. I have a set of mag lights. When I connected them in fro t of the pigtail, my blinkers work but at the same time the other blinker blinks very dimly. Does any one have a diagram for this so I can check my self.

 

https://www.f150online.com/forums/19...ml#post5135694

You already started a new thread - Please don't mutli-post - against forum etiquette.

Thanks.

 

Just joined the forum, thank you for the extra help in diagnosing the trailer tow light problems. Together we can help each other save money in the long run. I have followed everyone's advice, locations of the fuse along with tracing the problem. lo and behold one fuse was blown. now I am unsure about the relay.

 

The hot side of the relay is the truck signals and batt power. The fuses for the trailer are down stream of the relay if memory serves, but could be upstream, but independent of the truck signal system. Do yourself a favor if you pull a trailer fairly regularly. Go to NAPA and get re-settable fuses to put in place of the standard fuses. They reset once the short is removed and power is cycled making hunting down a trailer wiring problem sooo much easier. They are a lot longer than the standard fuse and require trimming the ridges inside the fuse box cover, but no more twisting around every time you have to trace a problem.