My blower on my central air unit acts like it is getting stuck. When I turn on the a/c it hums for a min then if I hit the outside of the blower it kicks in and starts blowing. Would this be bearings? This has been happening for a couple days off and on. Sometime it starts on its own and sometimes it needs a good wack! It is a rheem model #RGDA-075C-ER.

Thanks for any help

Matt

Sounds like loose wiring or a bad fan relay