SHould the heading bug (and alt bug) on the 4500s control roll and pitch of the Tru Track VSVG? What is the function of the autopilot source switch?

I have completed the troubleshooting procedure for the autopilot per the manual but it assumes an AF Pilot. I have no AP roll control with the heading bug. The autopilot source switch is set to output from the Arinc box.

Thanks,
Chris Stone