Trailer lights on 1988 B2200

I have a 1988 B2200 with a bumper that has a built in hitch but I have no idea how to connect this up with my 4 prong trailer lights.

I have removed one of the taillights and discovered that I have
5 wires as follows:

Green/White - Turn signal (right)
Red/White ????????
Red/Green Running
White/Green ????
Black ????

On the trailer I have 4 wires.
1 female white
3 male Green yellow brown.

I know that the green and yellow are for the right and left turn signals and I am thinking that the brown is for running lights
which would leave white as power.

I have read that I need a 5 to 4 converter but I have no idea how to actually connect these wires except to splice into the taillights themselves.

I would be glad to spend the money for a nice clean harness if such a thing is available. If not I am looking for any suggestions on accomplishing this in the best way.

Thanks very much,
Jim Lee

1988 B2200 - 180k+ and going strong

You need a trailer light converter. Should be able to get it at any parts store. This came up on a quick GOOGLE search.

Yes, you need a trailer light converter because your truck has separate brake and turn signal lights, and dumb vehicles like GM don't. I had to do this on a Jeep Cherokee in the early 1990s.

I suggest stripping off some insulation from existing wires, and soldering new wires to the bare copper wire, stronger than cutting such wires, and much more robust than using those %^&$#%&$^*$# crimp connectors.

Those things are crap. Good luck finding one to last!
I went through three of them in a week. Then I built my own. 12 years later, it still works.

I didn't have any issues with my trailer light converter in four years of having, came from Checker/O'Reilly.

Yup, I've never had one fail. Came from a parts store.