Heater Blower Motor did not come on until I thumped the cover...
 

Hello, Yet another issue with my girl. Day before yesterday I ran the heater blower for over 3 hours with no issue. Then yesterday I go in and turned on the blower and nothing, notta, zip, so I thought , Now What!? So I fiddled with the knobs a bit, still nothing, and decided that maybe if I popped her hood and thumped the blower motor cover that might get it running again, prayers.....So that is what I did and lo and behold....thump, and it started running again and has not stopped. I got back into the cab, shut the heater off, fiddled with all the knobs, turning it off and on, and it came back on each time. Low, med, and high, so what is it? Can the motor be oiled?
She is going in for her LIM and t-stat work next week, is this something that I should add to the list?
It is near to 17F on some days here, must have heater blowing heat!
Thanks Ya'll

This most often occurs when the bearings in the motor start to go bad. The vibration from hitting the motor allow the locked rotor torque to overcome the bearing friction and start spinning. Once it's spinning, it will likely stay spinning. So long as it doesn't end up in that same sticky spot again, it will likely start up. That is until it just won't some day.