GM A/C Heater blower module - Part # 12484912

Seeking general history, location, repair / replacement information about the module???

The GM garage charges $300.00 to replace this part - unacceptable

There are many cheaper suppliers. You local parts store may have them and there certainly is an assortment of internet suppliers with them such as: for $75.00 I would guess your other questions could be answered with Goggle as well.

That said are you sure that is what you need?