Volvo: 740 antenna motor, antenna switch, turbo wagon

Question
My 91 740 turbo wagon antenna motor recently stopped working. The mast had been retracting only to the top of the base segment for some time. The antenna plastic tail is intact. I have power getting to the plug near the motor, but would appreciate advice on how to troubleshoot the problem.

Answer
John,
You hear the motor working but not moving the mast, right? The ground wire is good and attached, right? How about the dash antenna switch is it on? If the mast is slightly bent it will not operate. Sometimes it gets so dirty it will also not operate. The antenna motor wears out after many years of use.
Check to see if when operating the antenna on/off there are two power supplies or only one. There is always with the key on a power supply to the antenna, when the radio is switched on there should be two power supplies, then when the radio is switched off there should be only one.