The blower relay is a fuse type block which relays power to the blower motor. Some also have a resistor unit built in, while other systems have this part separate.
A failed blower motor relay will likely see the blower motor not functioning at all, as power won't be getting to the unit.
Replacing the blower relay should be a simple repair once it is located.
We stock and sell a wide variety of quality blower relays from these manufacturers: