Sounds like problem I had with mine. I just removed rubber cover on blower motor itself, and reconnected contacts. Motor still is noisy on speed 2, but it works all the time.
I decided that motor is working ok, when connected directly to battery it blow full speed, so I ruled out motor itself, also checked all fuses and all were good, so only thing left was contact points.
I decided that motor is working ok, when connected directly to battery it blow full speed, so I ruled out motor itself, also checked all fuses and all were good, so only thing left was contact points.