That leaves the pressure switch out of the equation no? If a blade fuse is used to jump the two wires going to P/Switch that also checks the circuit integrity from there.Because what I suggested is easier than having to wrestle with the drier pressure switch. Most times thing are dirty or the connectors are stuck together, and it’s a bitch to separate them.Why not just bypass the ac pressure switch at the dryer to test the auxiliary fan motor and at the same time you’ll know if the switch is faulty.
The plug slides off the tstat sender right away, and all you need is a metal object that fits inside the plug. Presto, you can test the aux fan.
Also do what you suggest and the whole circuit gets tested and there are no unknowns.