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
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