heat and ac question on 1993 Toyota Corolla

my cooling fan only works with ac and not the heat why

1 answer
The condenser fan operates when the A/C compressor is engaged, as part of the A/C operation. No need for A/C when the heater's on.
You also have a radiator fan, it cycles on and off to cool the engine.
The condenser fan is on the passenger's side and the cooling fan is on the driver's side.