Air handler fan not shutting off why?

Question

So the question is really in the title.
My carrier air handlers fan will not shut off. I have done the following:

checked to make sure the fan was not set to on via the nest t stat.
pulled nest off the wall to see if the fan stopped, it didn’t
changed the only relay inside the air handler unit which was a T92P7F22-28 (I had tested the old one and it seemed to be functioning fine but at $10 why not).
Pulled the plug from the fan motor and put a lead to my multi meter at C and tested the leads marked N and L with the other end of the multi meter and read 120ish volts on each, so I assumed that means constant 240ish volts is being supplied to the fan motor.
breaker at the panel and of course breaker at the air handler unit will indeed finally kill power
ac condenser outside works fine, nest shuts it off when desired temperature is hit but fan never stops.
for kicks I got another nest, hooked it up, same issue
replaced the nest base that it snaps into on the wall, same issue
I also tested the fuse inside with the multimeter and visually it didn’t look fried, and the multimeter confirmed this.

I am somewhat out of ideas. There’s very few components inside the air handler it appears and anything  else modular looking just seems to be related to the electric heater inside of it. I am going to attach pics if they help.
Air handler model: FX4DNB or FXDNF

ThreePhaseEel · Accepted Answer

I'd replace the blower motor at this point
It sounds like the blower motor has an internal short in it that's causing it to run even in the absence of a speed command from the air handler control circuits.  I'd replace it with an OEM replacement part, as it appears to be some sort of module with an internal speed controller.

Air handler fan not shutting off why?

One Answer

I'd replace the blower motor at this point

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