Furnace Blower Fan Cycles On/Off During the off Cycle
Goodman model NO. GMP075-4 Blower Fan Motor turn on and off irregularly while the thermostatic FAN switch is at off position, error code are one blink then 4 then 5 blinks, then red LED light on constantly and fan still running will stop and on randomly, drive me crazy!!
lastnight Id spend over three hours to troubleshooting, did everything this video said, its not thermostatics, its not the cables, its not sensors, I bypass fan limit switch, cleaned the air filter, same thing happened, so I order the PCB B1809913S, will update!..Any Helps ?........................
PS: Goodman B13709-08 limit switch tested on 0.4 Ohm should be ok, cleaned flame sensor still the same.
PS: the furnace gas fire up and work normally.
Blower Fan Motor Won't Shut off!- STEP by STEP Troubleshooting!