issue with 118379 T-one Wiring Harness on Trailer turn signals

I have a teardrop camper with turn signals and brake lights that worked well with my RAV4.. my current vehicle is a 2002 Ext Cab Tacoma

I just installed aftermarket harness 118379 T-one Wiring Harness that I got from E trailer, and now the trailor lights act real strange.. it is the 4 prong hookup style

for example, when I put the left turn signal on, the trailer turn signal at the rear flashes faintly, but both side marker turn signals flash..

are there any known problems ??

I am going to find a friend with a vehicle with 4 prong to test my trailer again since it has been parked for some time since I successfully used it with my RAV4 ( which I lost due to insurance totalling it out recently )

any hints are appreciated.. I need to fix it within a week for a long trip...
I followed the instructions to install the wire harness on my Tacoma ,

However I will ask a friend with a four prong hookup on their vehicle
to test my trailer wiring to be sure it still works...

that being said, are there any known problems people have had with
polarity or hooking up the T connections ??

does it matter which connection goes on the vehicle wiring side of the
system and which connection goes to the trailer wiring side of the
system..

are there any websites that can help me with this troubleshooting ??


I am even considering buying a quick temporary turn signal kit and zip tying it to my small camper to get me home , but need to make sure first my truck lighting is correct..

much appreciated,

joe

 

That harness is rated for one turn/stop light per side (2.1 amps). Maybe your side turn lights are overloading it. I would think the side lights would not be connected to the turn signal, tho. I thought those were connected to the tail light, to be on whenever the lights are on. Perhaps the tail light and the stop light wires are switched in the trailer connector or the new harness. If you remove the bulbs from the side markers, do the signal lights work correctly?

 

thanks Azreb, I will give that a try as you suggested ...

if it is the sidemarker light issue, then I may try to disconnect those wires, at least long enough to get me home

cheers,
joe