In response to the poster, and possibly others, whose motor goes on when
he turns the radio on and off, I offer my own experience. This applies to
an '86 4000csq. When radio turned on antenna didn't go up, motor didn't
turn on. When radio turned off, motor went through its jpaces. Removed
antenna, opened it up. Cleaned points on both relays, bent relay frame
such that points were a little closer in open position. Reinstalled and
antenna has been working fine ever since (1 yr. c.a.). Could be if you
see no mechanical breakage in anntenna itself that it's your relay(s).
Hope this helps someone.