E39 sport head rest repair

I am having a problem with the head rest on my E39 540i sport seat. It appears to be dead? non functioning. does anybody know of a way to test, replace, buy a new motor to fix it?

First, is the motor running when you push the buttons?

Actually no. The headrest is no longer attached to the motor/ track mechanism either.
My passenger seat works perfect and I can hear the motor run.

Assuming the fuse is OK, verify power at the seat switch with a test light or multimeter and then either check for power at the motor or go further back in the circuit and check for power. If you have power at the switch but not the motor, check the harness for any breaks in the wire.