If I had to guess, this is a piper arrow dimmer circuit. The connection to ground pulls the landing gear lights to ground, applying full power and thus full brightness to the lights. When the dimmer is turned on, the aforementioned lights brightness level is controlled thought the bipolar dimmer. The other pot serves to control the avionics dimmer circuit, and also turns on the nav lights by connecting 1&2.
Just a guess.....
RV-10 - 1285 hours
First Flight Oct 2012
Aviation Partners, LLC
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