Air Conditioner / Heater Motor/Blower Making Noise

Last night I turned on my heater when leaving the restaurant for dinner. The fan up under the dash that blows or sucks in the air sounded HORRIBLE. A weird whining sound and just sounded all messed up. I looked up underneath the dash with a flash light and couldn't seem to notice or find anything.

Turned the air off... noise stopped... turned it back on, noise again...??

I left it alone and thought I would look at it again this morning in the light. Upon first start up, SAME issue... turned it off, let it sit for a minute.

Turned it back on, and noise is all gone? WEIRD!?! Anyone have this issue or any ideas? I don't want to continue to run it if it might cause some problem. Appeared to be an issue with or without the recirculate button pushed... but changing this mode did make differences in the noises.

Thanks in advance.