More research...D-86 shows motor relay board receiving 12V power at pin 5 and pin 2 is black to the motor. I'm guessing the black is the ground to the motor.
So, if I wanted to test pins coming from the I/O board to the motor relay board, could I just unplug the female molex connector and put my multimeter black lead into pin 2 and then the red lead in pin 5 to see if I am getting power TO the board?
As far as I can ascertain, I am not getting power FROM the board. If I do test power getting to the board, would I be able to similarly test the other pins to see if I am getting signal? If so, what kind of setting on the multimeter would I use to test the other pins?
Again, thank you VERY much for the helpful teaching and suggestions.