Driver Side rear... How easy is this to replace? Good source for a replacement motor! Thanks from Jeff T on my 51st B-Day!
First verify it is the motor and not the wiring or the switch. If it the motor itseld changing the brushes and cleaning the commutator may be all it needs.
check the window lift mechanism (see if there is a cause of the window lift motor to strain... could be an obstruction) as stated by flynbuick brushes and the spring to apply pressure to brush onto the commutator. As far as the commutator a electrical load (hi pot test) may be needed but this is down the road of last things to check. 1. check lift mechanism 2. switches and connection 3. pull window lift motor and start asking questions again how to rebuild
As jimhirt said, check for obstructions on the mechanism itself...then lube the hell out of it with white lithium grease.