Here's what's going on:
- Turn the Key (~11sec): This powers on the control board, drive cooling fan, and vacuum pump for brake vacuum. The click you hear is the first contactor closing. In fact, if you look hard at the contactor (small black box just above the hanging power connector on the right) you can see the contacts closing.
- Turn the Heater On (19-22sec): I have a ceramic heater element inserted where the heater core was. I can turn on the heat only if the fan is on 4, and a separate heater switch is on. In the video, you hear the blower come on, and the click on and off of the smaller heater contactor. This is switching the 144VDC to the heater element.
- Give it the Gas (~32sec): The accelerator cable is not connected yet, so I get out of the car and come around to the PotBox that will trigger acceleration. You hear and see the second contactor close (black box at the front of the board to the left) and in theory, now the power is flowing to and through the drive and you're on your way.