You say you changed the switch out to a known good one. Did you check to make sure they were the same type? The side of the switch will indicate the function of each pin, do they match. Other than that, according to the wiring diagram I have the door switch hooks up to pins 1-6 on the backplane. You can use a voltmeter to check continuity from that J10 connector on the harness to the pins on the switch. I'm done here.