Intermittent (old and new) AC blower motors

[RiggYaris]

Recently, my daughter’s AC blower motor in her 2010 Yaris stopped working. I read a Toyota Tacoma blog about the same problem, where one blogger gave the blower housing a tap with the handle of his screwdriver and it started working. Sure enough, when I just bumped the original motor, it started working. I assumed that was a sign the blower motor was about to go out completely, so I replaced it with a new one about 2 weeks ago.

Yesterday, the brand new motor stopped blowing! My daughter remembered I gave the old motor a bump, so she leaned over and just smacked the glove box door and the blower started working. Then, after her car sat in our driveway for a couple hours, the dang thing stopped working again as she was pulling out of the driveway! So she smacked the glove box and it started working again.

From what I've read, this is a common problem in a lot of Toyotas, but I haven't seen a definitive solution. Does anyone have any ideas where a short or improper connection might be that is causing this intermittent issue?

Thank you!