70 Duster rallye dash electrical question

The rallye panel has 2 circuit boards and a harness connecter for each. The smaller board has only 3 wires going to it. One of those is for the one illumination bulb on that side of the panel. There aren't many so they all need to work. The bulb sockets can be found at NAPA store. More than one size
so take a sample with you.