Where are the fuses located on an 07 Tahoe located? My right side mirror's heat works. The driver's side doesn't.

 

Probably not a fuse.
The heater circuits are supplied power from the door mirror switch control module. The signal to energize the heater is sent from the BCM via. GMLAN (Low speed serial data communication line) to the mirror switch control modules on both doors.

If you can you control both left and right mirrors with the drivers door mirror controls, then you have power and the GMLAN is working and the mirror heater element or the wiring to the heater is probably bad.