To find the correct fuse:
1. Consult your owner's manual: This is the most reliable source. The manual will have a fuse diagram showing the location of all fuses and what circuits they protect. Look for a fuse labeled "seat heaters," "heated seats," or something similar.
2. Check the fuse box diagrams: There are usually two fuse boxes in a 2004 Chevy Tahoe: one under the hood and one inside the vehicle, often under the dashboard. The fuse box covers usually have diagrams printed on the inside showing which fuse corresponds to which circuit.
Without your owner's manual or access to the vehicle's fuse box diagrams, it's impossible to give you a precise answer.