The AC/Heat blower motor on my MCS makes a squeaky noise sporadically, at any speed. Any idea what causes it and how to rectify it?

 

Short of replacing the blower...lots of time, you can try to lube it. Worked on mine.
Remove the cabin air filter, and if you become a bit of a cortonistist, you can reach up the duct, and reach the fan. I put a bit of lithum grease on my finger, and put some on the ends where the fan (it is like a hampers's exercise wheel)where it is connected to the motor. Seemed to have solved my issues. I also used a mobil1 spray lube with an extra long tube to do the same, using my finger to point the end at the exact spot, then other hand to push the button on the can...ouch!!
Had to do it 2x in the last 4 years....both ways seem to work well. Careful on overdooing it....could make a mess...just a dab in the right spot is all it needs.

 

zippyNH
Thank you for the tip. A weekend project soon.