Been having troubles with my furnace lately. Model #h9mpv100j20d1 thermostat send the call for heat. Click and all the good stuff. The furnace starts up and runs. Then shuts down due to the blower not engaging. However I can repeat the process and set the thermostat to have fan on and the blower starts and continues.
I just finished replacing the ecm control board and same results. Had a tech out a week ago this is what they diagnosed as the issue. Still same result. Any one else ever have this issue?
Does your fan motor have a silver end cap? That module controls fan speeds and is likely faulty. It can be replaced separately from the motor.
Does the blower fan start in cooling mode?
Switch the blue heating wire with the yellow spare wire on the motor.
If the continuous fan speed is still working maybe some of the others will as well. It would be easier on your heat exchanger to run a higher fan speed then low speed continuous, until you get it fixed.
Thanknyou for the advise. I'll have a look and try out those recommendations tonight. And report back.