truck/trailer light wiring question

I got some white truck/trailer lights for my hatch and they did not have documentation. They appear to be the same as all other truck/trailer lights so I'm guessing somebody knows how these have to be wired.

They have red for power, white appears to be ground, and then there is a black for stop/turn which does not seem to do anything. If I want to just run the lamps at full brightness what do I need to wire up?

If the lamp has three wires going into it here is what they will be:

Ground
Stop/Turn (one of the others, whichever makes the brightest light)
Tail (the other one, will have the dimmer light)

Play around with them until you find the right combination, having the colors red, white, and black suggests that black is ground, in the trailer wiring world white is ground and black is +12VDC, but there would be no reason for +12VDC to go into a lamp.

the plug is labeled

Ground (white)
Tail (red)
Stop/Turn (black)

the only combination that does anything at all is Tail (red) to power and Ground (white) to ground. Stop/Turn (black) does not do anything no matter whether it is plugged into power or ground, or whether any of the others are plugged in. Should it be 12v?

Lamp is bad then, either the bulb is burnt or you've got a bad connection.

Right now the dim circuit is the only one working, stop/turn is the bright one.

I have two of them and they are both the same. I called the vendor support, they pulled one off the shelf and got nothing. Bad batch I guess.