Ran the power seat all the way up to clean under the seat and NOW the front portion of seat will not go down. Motor hums, but seat remains all the way up.

Rear of seat and forward and backward functions are fine.

Any suggestions?

 

If the motor hums, that's the good news. Most likely means only the worm drive gear is disengaged from the track gear; could be only a bushing if you're lucky.

Do you hear a clicking at all? Any gear bits under the seat?