To be certain, I highly recommend:
1. Consulting your owner's manual: It should have a diagram showing the location of components under the dashboard.
2. Searching online for a 1993 Chevy G20 repair manual or forum: There are many online resources with pictures and instructions specific to this model. Searching for "1993 Chevy G20 blower motor resistor location" should yield helpful results.
3. Checking online parts diagrams: Auto parts websites (like AutoZone, Advance Auto Parts, etc.) often have diagrams that show the location of parts based on the VIN number of your vehicle.
Remember to disconnect the negative battery terminal before working on any electrical components.