Factory Trailer Harness Problem. Help me please

I have the factory harness on my 04 tacoma, i have only used it 5 or 6 times, and now when i go to plug my trailer in the brake lights dont work and only the right blinker will work. Also, when the 4 way flashers are on, still only the right tail light blinks.

I drove my truck to Lowes and plugged in a new trailer and it has the same problem, so it is something in the truck. What could be the problem?

 

check all the connections for the harness

 

Get a test light and start tracing your problem backward from the wiring harness until you find the disconnect. Start with the simple stuff, make sure all connections are plugged in and snug. Once you've eliminated the connections as the culprit, start tracing the problem with a test light.

 

do you think it could need a new tail light converter?

 

could be a bad wiring harness mine was bad ive replaced it with a new one and everything works great now.

 

On mine I had a seperate fuse that was blown, that was not in the normal fuse panel it was in the access part of the cab located in a storage compartment, behind the drivers seat.

 

that is strange, i have never heard of a fuse panel back there. I have a single cab though..

 

The same thing happened to me.
I had to swap out my converter that plugs into the tail light.
I checked the ground first on the converter, then reset all my connections (unplugged, dielectic greased the fittings etc & fuses.
Finally tried another trailer & had the same result.
Swapped out the converter box with a new one, worked like a charm.
G/L

 

Happened to me as well. Still haven't replaced mine yet. It's on my list of things to do before summer.

 

was it an easy swap. Like, did you just buy a converter, cut the old one out and splice in the new converter. or was there more to it?

 

yes I just bought the converter from Amazon. You can get them at Autoparts stores, etrailer much cheaper than dealer. I learned that on here.
It plugs rights into the tail light harness so take out tail lights, unplug old converter, plug in new one. You do have to thread the wires for the flat plug to come out by the receiver. I used the plastic wire loom & zip ties to keep it clean & up out of the way. It was not that hard at all.
There is a newer one (toyota part) that goes all the way up to the front of the motor but I just use the cheaper model for all our trailers are 4 wire.
There was a youtube video for it lol...