When starting upper oven, burner will turn on but no blower.

When starting lower oven, blower turns on as normal.

I can't tell if there are separate blower motors on this oven or if one blower is shared.

Does it appear that I need to replace a blower or a circuit component?

Thanks for the help.

EDIT: I have just learned that my oven only has one blower. That would mean that my problem is in a circuit. Any suggestions as to where to begin with this?