If your power radio antenna won't go up and down anymore, the problem is either a burned-out motor or the geared cable inside the mast. Both are easy DIY fixes. First, make sure the motor works.

If only your vehicle had a glow-in-the-dark antenna to make it easier to find, you wouldn’t be in this situation. Faced with just such a problem himself, Instructables user [botzendesign] has ...