Race Technology

I understand that the switch lines need to be grounded when that button is pushed, but to what ground?

I note that there is a specific common/ground for the switches, but electrically that does seem to be the same as the D2P's main ground, so is the switch ground required? Could the buttons just connect the switch lines to vehicle ground and not bother with the switch ground line. Or could the buttons connect to ground and the switch common line from the D2P also be connected elsewhere to vehicle ground, would that be the same?

I want to eliminate having that common/ground wire between the switches and the D2P. I'd like to just have the 4 switch lines and use vehicle ground as the switch common. Any problems with doing that?

To answer my own question, I connected the Switch Gnd from the D2P and also the common to the actual switches to the vehicle gnd. and everything is working as it should. This means I have just the 4 wires running from the switches to the D2P, as I wanted.

Not sure what happens if the D2P's Switch Gnd. is not connected in this way though. Since when I tested it there was continuity to the main D2P gnd. it still ought to work, but didn't try that.