I just finished replacing the GE motor in my unit with a Mars blower motor. I had the same issue, one extra wire. But there's a chance the orange wire is actually the common wire and the yellow is one of the two med settings (med hi or med lo). That turned out to be the case in my unit. On my new motor, I had black, red, blue, and yellow.. A 4-speed furnace blower motor wiring diagram typically includes information such as the color-coded wiring connections, the terminals on the motor and control board, and any additional components involved in the motor's operation. It may also show any jumper wires or additional wiring configurations that may be required for certain.
PSC wiring diagram courtesy of: Packard Instruction Manual. EC Max wiring diagram courtesy of: Packard Instruction Manual. There are 3 main sets of wires. The white and black are taped together and go to the L1 and L2 pins, respectively. The black and red wire are also taped together. The black wire goes to the "Cool" port.. wire) SEE FURNACE BLOWER LABEL FOR APPROPRIATE SPEED CONNECTIONS Furnace Operation (orange wire) NOTE: See furnace installation instructions for nominal air deliveries. LML Furnace Model No.-010, -012, -015 Relay Box Speed Terminal (minimum)-017, -020, -023 LML. 4 For E2E(-) furnace only: b. Attach the appropriate brand label to the sheet