Not sure how you get to it on a 45C but you should be able to replace it with the new style Turbo Vac blowers. Another HOFer replaced his and has had great results. I have one that is getting weak and will most likely put one in. You can DIY it as long as they will fit. I was told by CruisAir that they will fit as replacements for most of the squirrel cage style blowers. If you've got the old open fan design you might be better off replacing the whole air handler. I believe you can get a replacement motor from Grainger if CruisAir no longer stocks them.