strong odor from heater and engine compartment.

Purchased a 2003 Baja in June '10 with 95,000 miles. When running heater through winter months had strong smell of burning rubber ftom interior vents. Mechanic says the smell is from hot electrical components in heater coil. Through the warm summer months the smell continued and seemed to be present under the hood when engine was hot, but not in cab when running AC. Any thoughts? Everything works well, just smelly sometimes.