Means of adjusting fan speed on Bryant gas furnace
When you look at the motor there are 7 wires. 2 brown for the capacitor, a White common wire, Black for high, orange for medium high, blue for medium low and red for low. It comes from the factory with the black plugged into cool and the orange plugged into heat. Blue and red are hooked to M1 and M2 which are just place holders. To reduce speed swap the orange wire with either the blue or red wires on the circuit board. I have to warn you however that low air flow can damage the furnace and actually be less efficient. You should take the temperature at the outlet of the furnace and at the inlet of the furnace. Subtract the two, this will give you your split. Compare that to the required split on the nameplate of the furnace. If it is too high you need more air. I have seen cases where the furnace is too large for the ducts and was overheating even on high speed.