It’s not such a simple on-off switch:

Stripping down the gear lever you can see it is quite a complex affair.

There is actually a solenoid which locks the gear in the down position until the aircraft is in the air. Surprisingly the gear locked in place when I moved it to the down position with no power supplied.

Stuck in the Gear Down position

Back to the drawing board to see how to activate the solenoid, and to get the bulbs functioning.