I have a Goodman GMP forced air furnace running on natural gas. It is about 5 - 6 years old. It recently went out. The draft inducer would come on and the igniter would glow but then it would shut down without opening the gas valve. I checked and found that the board was never sending a correct voltage to the gas valve. After checking all the safety switches and pressure switch and limit switches I bought a new B18099-13 control board and I will be installing it today.
Now the wiring diagram on the furnace is quite good. The only difference I see is in the wiring colors to the blower motor. The diagram says I should see a white neutral, a black high speed wire, a blue medium speed wire and a red low speed wire. I think the motor must be a four speed. It has a white neutral, a black, a yellow, an orange and a red. I know how the wires came off and I should be able to get it back together but I would like to know what the blower wires actually are for and should one of them go to the M2 connector.