dwg2010XRT

What fuse # and where is it located? I have the same problem.. I know its not my trailer, so must be a fuse, just not sure what # and where it is...

Bigibinks

Just went through the same ordeal as the OP. My relay was still in the glove box (after 8 years lol). But of course the relay only allows the truck to charge the trailer battery. I found and checked both the fuses for the trailer brake lights and turn signals... both blown.

They are #s 36 and 42 (top extreme right and left, 10A, under passenger dash.
(in my 2004 anyways).

blueovelboy

what year truck?
09+ its #9 and #21

davbeab

I have a 2012 F150XLT SuperCrew. Trailer lights were working fine until I rented a U-Haul trailer. I didn't notice the lights on my trailer weren't working because I still had tail lights. Backing up to my garage noticed no brake light reflection. After investigating found I didn't have brake or turn signal lights. I checked the plug and had no power except for parking lights. I checked all fuses related and they looked good, finaly I pulled #73 fuse(under the hood) and with a magnifying glass could see the fuse was blown. Just a hair gap you could barely see. Replaced fuse and all is good

The Macf

2013 Raptor plugged in the #9 relay and #21 fuse. Hooked up a positive to the orange wire in the trailer harness and have no power. Used a test light clamped to the exposed copper and grounded it out. No light = no power.

Coastline

The key has to be turned on. To make it HOT all the time (even when key is off) make a jumper about an inch long with a spade connector on each end, replace the relay with the jumper and you have power on all the time. The only problem with this is if you leave the trailer plugged in for a long time (several days) it could drain the battery because it is constantly charging the breakaway brake battery.

tgoller

Got the same issue with my F150. Wife and I just bought a 24' camper and I don't have left turn or brake and four ways aren't working properly (both flash but left side is very dim and doesn't flash with right). I thought it was a ground issue so I removed the ground bolt, dremeled the rust off the frame, bolt and connecter on the ground wire but lights still don't work. Having this issue with both the 7-pin recepticle and the 4-pin flat plug.

Any insight?

joefrog

I had no running lights, brake or turn signals on our camper -- happened all at once. I had the dealer check my output from the truck, it was all just fine. I took the camper to the repair shop, he found a broken ground wire underneath. He said that I could've run over something on the road and caused it.

Cobra82

I replaced bulbs, traced electrical lines, sanded rust from hitch, and about everything else mentioned. After lost hours, I decided to replace fuses, after hanging upside down inside looking for a blown fuse--which I never found. When I replaced fuse 73 under the hood--a 20 amp fuse controlling TT stop/turn lamps relay power my lights began working fine. I never noticed a blown fuse anywhere on my truck, but I replaced every fuse having anything to do with turn signals or stop lights. Most are made in China anyway...Try this before buying all new lamps!

raisin

Etrailer sells 7-pin test connector that you can pop into the 7-pin on the truck. Fuses for truck and trailer lights are different. They've been putting that fuse and relay in plastic bag at least from '99. If you think ground may be bad have someone hold a wire on A-frame bolt and truck bumper and check again.

Have some spare fuses, Best way to check fuses, swap in new fuse. I always put cord (ball and loop) around 7-pin cover and trailer connector to keep connector from coming out. It happened.