At the bus where the switch connects to the board, You can remove that plug, and expose the pins on the board. If you momentarily contact pin marked GND (black) with any of the primary color marked pins, red, green, blue, or yellow, that particular Aux (relay) should energize or "click". You can also do this without removing the plug, just touch the points that look like the top of a flat head screw. I would choose any color but red. The red aux is usually reserved for the Spa, and depending on your system, may not energize a relay. But if you have a pool or spa light wired to the remote for example, you should be able to turn it on, or more importantly hear the click that confirms proper operation of the board and rule it out.