Still trying to fix my lack of hi-beams. Managed to remove my steering wheel in order to remove and replace my existing combo switch, but replacement one(s) I ordered, both new and used have
wiring harness that are too short! So back to the drawing board to try and trouble shoot my original combo switch and to try and correct the lack of hi-beam issue...any idea(s) on how to diagnose failure
point(s) in the combo switch? Thx!

 

This is from the FSM:

combo switch check

I take it you have a tilt steering column (since you said the wires were too short on the switches you found). As far as I can tell the 79 tilt column combination switch is specific to the 79 models only and there doesn't seem to be an aftermarket one available. If the switch is bad you could probably tap into the combo switch wires and mount a separate switch under the dash or something to control the high beams.