For the past two months or so, the exhaust blower would make a squealing noise at times and it acted like it wasn't pulling air through like it used to. Well tonight while having supper, i noticed that the glass was all black, and the flame very lazy. Took a flashlight and looked in through the back and could see that the motor wasn't turning at all. Everything else was working. Room blower was going, auger still feeding. How much of a job is it to replace this? Does anyone have any instructions of how to do this? Of course it is a corner install so I will have to unhook the vent and turn it around to get at it.