Problem with trailer lights on 2014 Yaris

[RWey52]

I have a 2014 3-door hatchback. Installed a hitch, and then bought a 5 to 4 converter box at O-Reilly's. Upon inspecting the tail light wiring under the removable covers, there's two wires going to each bulb. One switched hot ( +12 when called for ), and the other is a white/black tracer. I concluded the white/black is the common for each bulb, but this wire does not ohm out to the chassis ground. They do however show 0 ohms between two different wht/blk wires. I'm thinking they probably run a looped circuit for each bulb for diagnostic and burnt out bulb detection ???

Anyway, I hooked up the four signals properly ( running lights, brakes, left and right signal ), then I chose the white/black wire from the brake bulb for the ground.

Before I go further, the trailer IS wired correctly and IS functional. When plugged in, however, the only lights that work on the trailer are the running lights, which flash when the signal is on. No break lights.

Is this a problem with the discrete ground wires going to each bulb? Am I mistaken assuming all white/blk wires are a common ground ?

Thanks for help.

[CTScott]

White/black are chassis ground.

Just to verify your wiring to the 6 pin connectors for the tail lights:

Pin 1 - Blue: Stop Light
Pin 2 - Sky blue (Right) or Yellow (Left): Turn signal
Pin 3 -
Pin 4 - Green:Tail Light
Pin 5 - Red: Back up
Pin 6 - White/black: Ground

How are you feeding the switched power?

[RWey52]

White/black are chassis ground.

Just to verify your wiring to the 6 pin connectors for the tail lights:

Pin 1 - Blue: Stop Light
Pin 2 - Sky blue (Right) or Yellow (Left): Turn signal
Pin 3 -
Pin 4 - Green:Tail Light
Pin 5 - Red: Back up
Pin 6 - White/black: Ground

How are you feeding the switched power?

I'm not using switched power nor have I found the connector you listed. Where is it? I'd simply download a schematic, but every damned page wants credit card verification; my first born; or a commitment to purchase a timeshare in Tuvalu.

Currently I'm tapping off the wires on the left tail light assembly, with one wire of the converter traversing over to the right tail light for the right turn signal. It's not rocket science and a similar 5to4 converter worked on my 2008 Yaris, tho the tail light assembly was completely different. Nevertheless, on that vehicle I simply found the lines, tied them to the converter, tied the converter ground to the chassis, and it worked.

I have a 3-door hatchback. I'm assuming that the multiple wht/blk wires going to the various bulbs are all tied together at some point, and thus my decision to use just one of them ( from the brake light bulb ) should work just fine.

I guess my basic questions are this:

1) Are all the wht/blk lines on each bulb common? If so, why don't they ohm out to chassis ground?
2) Will a standard 5 to 4 converter work?


Why does this have to be so difficult? Did I purchase a dead converter ?

[CTScott]

I'm not using switched power nor have I found the connector you listed. Where is it? I'd simply download a schematic, but every damned page wants credit card verification; my first born; or a commitment to purchase a timeshare in Tuvalu.

Currently I'm tapping off the wires on the left tail light assembly, with one wire of the converter traversing over to the right tail light for the right turn signal. It's not rocket science and a similar 5to4 converter worked on my 2008 Yaris, tho the tail light assembly was completely different. Nevertheless, on that vehicle I simply found the lines, tied them to the converter, tied the converter ground to the chassis, and it worked.

I have a 3-door hatchback. I'm assuming that the multiple wht/blk wires going to the various bulbs are all tied together at some point, and thus my decision to use just one of them ( from the brake light bulb ) should work just fine.

I guess my basic questions are this:

1) Are all the wht/blk lines on each bulb common? If so, why don't they ohm out to chassis ground?
2) Will a standard 5 to 4 converter work?


Why does this have to be so difficult? Did I purchase a dead converter ?


The connector that I am listing is the one that plugs into the back of the tail light.

All white/black wires are commoned to chassis ground. What are you using as your chassis reference point when measuring?

If your converter has an ignition switched power wire, than that must be used and fed from something other than the feed to the bulbs. The older style 5-4's did not require ignition switched power, but many of the newer ones do.