At this point you don't need to buy anything. I assume it's working now based on the tech's job story. If it does stop working again, you will be in need of a blower motor regulator, which attaches to the blower motor. These two parts are normally replaced together, as if one has gone bad, it is likely the other is close behind (kind of like overvoltage protection relays and fuel pump relays on 124 cars).
\'06 E 350 (Yes, it\'s loaded)
\'04 G35 Coupe 6MT (Traded in 4/06)
\'02 CLK 55 //AMG (RIP 8/04)
\'97 C 230 (Traded in 12/04)