Please ignore the last post...I wasn't thinking...MIDI light will not come on unless MIDI is being transferred to the keyboard. So that has nothing to do with my problem.
I'm gonna try to explain this better. I want to use my keyboard as a controller when using software instruments. When I connect my keyboard to my MacBook using a Hosa MIDI-to-USB interface cable, GarageBand detects the keyboard, but when I play the keyboard, nothing happens in GarageBand.