Need help wiring truck to small trailer

Ran into a interesting issue today. The municipality I work for owns a 2016 International 1 ton truck. It got hooked to a trailer that our other 1 tons hook to and it had no brake lights. Upon closer inspection I found that the IH 1 ton trailer plug is wired like a heavy truck using 3 wire system ( signal is sepperate from brake light wire). Our other GMC topkick 1 tons have the trailer plug wired like light duty automotive wiring (2 wire signal light and brake light share same wire).

Rewiring the trailer is not a option as the other 1tons will still need to hook to it. I realize the 3 wire and 2 wire designs are done in the signal stat my question is how would I go about converting the IH truck over to 2 wire. Do I need to reroute wiring in signal stat, or do I need another style of signal stat, or is this achieved through the body control module? I did a quick google search and did find that "curt" makes a 3 wire to 2 wire convertor. Basically I wire ground, both signals, tail light, and stop light wire to one side and the output is ground, tail, left signal, and right signal. I ordered it and will have it tomorrow morning and will post if it is what I needed.

Has anyone else ran into this problem and how did you or do you correct it with out the convertor?

 

I was able to wire in a 3 wire to 2 wire convertor and fit it inside of the junction box. I also have been told thay IH dealers will have literature on this basically there is a couple wires that get connected differantly at the body controller. I will call dealer monday. Thanks for the suggestions.