Cabin Air Recirculating Button No longer works (1993 Accord)

Greetings,
I recently realized that the Freon was low in my 1993 Accord (slightly
cool air, bubbles/foam in sight glass). While awaiting the arrival of
the refrigerant (R-12) I will need to top it off, I realized that, while
trying to maximize what cool air was available by switching to
recirculate shortly after starting the car, the switch does not seem to
operate properly. I seem to remember that when pressing this button, the
fan force would increase noticeably. I can detect no difference in sound
or force of air flow when pressing the button. All other air controls
work properly. If this is a stupid question I apologize in advance, but
can this be related somehow to a low refrigerant situation? Is there
some kind of override that disables air recirculation when refrigerant
is low? If not, what is the probable cause/repair for this problem.
Initially I checked the fuses (all were fine) but quickly realized this
was pointless because all other air flow/speed controls were operating
normally. I hesitate to take the car to the local dealership as they
have raise my suspicion & lost my trust as a result of a "free" vehicle
check at my last oil change in April.
Any help or ideas are welcome & would be very appreciated.
Regards,
Rich