My apologies for not providing enough information, but despite that, you actually helped me quite a bit.
FSUIPC Version 4.974
FSX, SP2 10.0.61472.0 (fsk-sp2.20071210-2023)
Presently using the FSX Mooney aircraft, with a G5HSI model downloaded from FlightSim.com, but I had tried other standard controls as well (flap switch, speed brake, landing gear, etc.).
I do plan to create macro's with multiple controls in each file but thought I would start with a single control, just to be sure I understood the process. After reading your comments, I went back and tried to create a macro using a different aircraft (the FSX Cessna 172) and controls. After clicking several standard switches, I bumped into a couple that worked fine. It looks like my problem is the issue you mentioned about the "...C/C++ gauges programmed with the FS toolkit" being the ones that will work, if I understood you.
Is trial and error the best way to determine if a control is conducive to being controlled by a macro?
Thank you again,