1999 Mitsubishi Diamante AC not cold unless car runs 40mph

The condenser is in front of driver side (L) of radiator, but the auxiliary fan that turns on when I turn the AC on is on the passenger side (R). The (L) fan kicks in when engine temp is high but shuts down when normal operating temperature is reached. Problem is that in stop traffic when this driver side fan is not operating there is no heat dispersion from condenser. Have not checked relays that control fan speed. Are these fans inverted? How can I make the (L) fan operate at all times (bypass thermostat perhaps?) Please help, summer in Florida is HOT and traffic is a nightmare.