I think the earliest point you can read the VC is on the CN5 ribbon cable (9-10) on the Relay Pilot board. Or a little easier on the J2 plug (10-14) but no reason that should be different than the test points on the Relay interface. But if it’s always positive here, I would try pulling the J8 plug just to make sure nothing down the line is affecting it. And if it’s still always positive, are all your power supply voltages good?
Hey, I wonder if you have a dip switch in the wrong position on the MSU. Do you have the procedure for setting up the VC command?
