Originally posted by Big Jim:
Most likely the mast has stripped teeth on the plastic "whip" end that scrolls up in the motor. Between a slightly bent mast and slightly worn teeth, either one or both, the teeth don't catch on the mechanism in the motor.
Usually you just need to replace the mast. Part runs about $40.00.
This is what happened to mine, the last/first 2 inches of the plastic whip actually was broken off inside my antenna motor. I went to the dealership, paid my 40 some odd bucks, took the antenna motor out, opened it up to get the last piece out of the track/guide. I then, put the motor back in the car, and how you put the new antenna back in is you have to turn on the radio, wait for the motor to stop, then put in the plastic whip. (Make sure that when you put in the tail end of the whip, the antenna is fully extended, it makes it easier.) Then turn off the radio, the antenna motor will start to pull on the plastic, and will stop when the antenna is all the way down. You may have to feed the antenna a little, to get it to start going down.
