Hi Chris;
Piper used the Inst lts/nav lights rheostat to control both circuits. As i understand it, when the switch is rotated all the way to the stop in a counter clockwise direction, the nav lights are off and the instrument lights are off.
Immediately after rotating the switch off the counter clockwise stop, the nav lights circuit is energized. Further rotation in a clock wise direction controls the intensity of the instrument lights.
This set up is common to a great many Piper airplanes.
I took that switch out of my Comanche and installed a discrete switch for my nav lights and a MaxDim instrument light controller for my instrument lights. Check out the specs on the Max Dim light controller at: https://www.maxpulsemaxdim.com/.
If your switch/rheostat is beyond cleaning up, I’m pretty sure you will be able to find one at one of the major salvage yards. FWIW, the MaxDim unit, although expensive is modern technology and as such, will use much less power than the rheostat based system.
