| I'd be tracing and testing the voltage all the way from the 120 volt supply voltage to the transformer, through the limit switches, the input to the cicuit board as well as to the inducer motor.
I'd be testing that to ground (G) on the circuit board, and also checking using the neutral wire of 120 volt circuits, such as the neutral side of the inducer motor plug.
It's easy to leap to conclusions, but sound diagnostic procedures involve double checking things and explaining things that don't seem right, such as the discrepancy between voltage reading at the inducer motor and the same circuit at the circuit board.
I'd probably also supply some 120 volt power to the inducer motor to verify that it will work when it gets proper power, and jumper out the pressure switch to verify that the rest of the ignition cycle would start if the unducer fan were coming up to speed and making the pressure switch. If those two things test out, then you can concentrate on an explanation for why the inducer motor wont start.
Doing those tests would take me ----oh, ten minutes.  |