Front Blower motor not working

My front blower motor stopped working suddenly. Does not work at any speeds. A/C is working, I get cold air coming out of the vents when I'm on the highway. All fuses check out OK, both on passenger side panel and on right hand side fuse block under the hood.

Rear blower works fine.

Thanks in advance for troubleshooting advice.

EDIT: 24 hours after writing the above, blower motor works again, all speeds work fine. I did absolutely nothing to fix it so far. Seems like an intermittent problem. I would still like to look at a troubleshooting tree to pinpoint the problem. Thanks for all the replies so far!