I'm with Brett on this own - that was from mice. There's probably a skeleton or two in the ducts. However it did add a little weight which those fans can't handle, there was a shitload of dirt and crud inside the actual motor but the real killer, I am sure, is that with the fan blades blocked the fan would have freewheeled and burned out from excessive speed/current flow.
Marke, was going there anyway to get the trailing arms etc so just grabbed it for the hell of it. I will be by to get those lug nuts tho.
Richard, actually really easy to do - dunno if 1g and 2g are different but I was actually able to just drop the three screws and pull the motor down out from behind the glovebox - no dash removal required. The heater box itself, I suspect that would be a different story.