Blower Relay

Hi folks, recently I replaced my blower relay and my AC and heater worked fine. That was couple months ago, and now the relay blew again. Any ideas on what may be doing that?

What is blowing on the relay-the coil or the contacts? If the contacts are failing, I would expect the blower is drawiing too much current because the bearings are going bad. I don't know why the fuse wouldn't have blown though unless the fuse is of the wrong value.