As your jacks are now 10+ years old, you will find that the motors on all your jacks will need attention. Fortunately in most cases, there is nothing required besides disassembly, cleaning, and lubricating. To get a sticky one running, usually just crawling under and taking a pliers to the motor shaft and rotating it a little will get the jack running again but unless you do the maintenance, it WILL fail again and quite quickly. There are good youtube videos out there. What you will do is remove the electric motor, clean the brushes and brush rigging, and put some fresh grease on the gears. Over time, carbon and dirt build up make the brushes sticky in their guides and they fail to make contact with the commutator. A little time consuming but not difficult job.
