The problem with my radio antenna is not the mast. I can get the motor to spin by feeding power directly to it when it is on the workbench but it will not work when put into the car. I have tracked the culprit down to a black box that is affixed to the mast above the motor. There are only three components to the system, the motor, the winding gear, and this black box [in addition to the mast itself]. I am assuming this box decides how far to retract the mast but am not sure.

I am considering cutting open the box to see what is inside and to see if it is repairable. Has anybody done this? Would like to read about your experience.