When I turn my home heating unit on, Fan on Auto, I hear the gas come on and ignite, but the fan doesn't come on. I hear a buzzing noise coming from the Ignition Control unit. If I turn the fan on, the house heats nicely, but the (Robert Shaw 180 715U) Ignition control unit keeps buzzing. Any tests or suggestions?

I just posted this I meant a Robert Shaw 780 715U

Brand of furnace?
Exact model number of furnace?

Sears Power Miser
Model # 867.762621
Serial # 8331 75913

Maunfacturer (very faded info here) looks like SUGF 075AG02

The item that is buzzing is the ignition module which has little to do with the blower itself. If you turn the fan to on and it works then the fan motor itself is good but the heating fan control device is probably defective. They can be a fan and limit on some units as in the picture below.