GE PGS930SEL1SS slide in oven pre-heat functions in bake and convection modes shut down when temp reaches approximately 240-250 deg. I received the following failure codes in ERC mode:

Fault 683 (Inactive / 1 Occurrence)
Fault 350 (Inactive / 11 Occurences)
Fault 352 (Inactive / 1 Occurrence)

I have tested the blower motor in service mode and it hums but does not come on. I inspected for blower blockage and there is none. The blower spins freely by hand. I also connected the blower motor directly to 120v bypassing oven wiring and the fan comes on and spins fine.

I replaced the machine board but, it did not fix the problem.

What else can I try or does someone have a solution to fix the blower motor coming on which should fix the pre-heat issue?