1995 Toyota Previa No Heat

Purchased Previa recently when you turn on the heater all it makes is a click sound and nothing else. I`ve checked the fuses in the fuse box all are ok. Do you think it needs a new blower? I have not checked to see if the a/c works. Also the rear makes a roar type sound the previous owner said it needs a new diff but I`m guessing it might be the rear wheel bearings. Any suggestions thank for your time.