To find it, you'll need to consult your owner's manual. This is the most reliable way to locate the specific fuse for the blower motor. The manual will have a diagram of the fuse box(es) and clearly indicate which fuse is responsible.
There are typically two fuse boxes in a Rendezvous: one under the hood and one inside the vehicle, often located under the dashboard. The blower motor fuse might be in either location. Your owner's manual will tell you which one.