Trailer hitch wiring yaris 2012

[Strider199]

Originally Posted by CTScott

Bulbs definitely draw more current, but unless someone installed some crazy wattage bulbs, the converter should have taken care of the issue. Can you take some resistance measurements on the trailer connector to see what you measure for each of the three pins to ground (assuming you have a 4 wire connector)?

Also, to verify your wiring, one the 2012 tail light connectors:

Taillight - Green wire on either right or left
Stop - Light blue wire on either
Right Turn - Sky blue wire
Left turn - Yellow wire
Ground - White/black (or bare metal bolt connection)

Those are the colours I connected to on that D-shaped connector going to the left tail light, the ground is mounted under the nut/stud coming from the light CTScott.
The bulbs on the trailer are just standard trailer bulbs which work great when hooked up to my Dads 2007 Yaris. I will try and get a resistance reading as you suggested (yes it's a 4 prong plug, one being ground) when the weather clears.
Could it be a faulty converter? I've never come across one in my time but I'm tempted to buy another one to see if thats it.