I'm upgrading my boat trailer to Disc brakes. This requires the installation of a solenoid valve in the trailer hydraulic line, which cuts the disk brakes out during reversing. For the cut-out, apparently the back-up light circuit is used. The adapter I got with the 02 4WD Duramax is a four pin unit, one for ground, which worked well on the drum brakes.
My question is, will a 7 to 5-pin adapter like the "Hoppy" p/n 47375 sold by after marked work?

My boat is in Mexico and I would like have the right part before I drive down.