No electrical power

Greets,

Starting from cold & dark, with and/or without ground power, starting the APU is successful, the blue light enables but clicking to couple the APU generator to the bus does nothing. Also, there is no air pressure noted.

I've followed tutorials 1 & 2, and cannot figure out what I am missing.

Has anyone had this issue?

I appreciate any help that may be offered.

Thanks

Chip B.