Three machines new Feb.2014. Replaced all 3 original heater assemblies by 4000 hour mark. The replacement assemblies we received are quite different internally, I'll call them 2nd generation, have performed much better, just had one fail at 14,000 hours.
Have had a lot of fuses "melt". By this I mean the fuse isn't blown, the little fuse spades/terminals get so hot where they make the connection in the fuse block that they actually melt the fuse plastic and sometimes the fuse block itself. Poor connection =high amps= heat=meltdown ?? My guess.
I do not really care for the "variable speed" feature of these blowers/fans versus the old school 3 speed on the older style BT's, I have zero info on how to begin testing these newer assemblies, so just replace the whole thing. I'm assuming that is cheaper than the parts and labor to try and rebuild one. I could be wrong?
Hope this helps?
Are you having issues?