Antenna not going down

Not even going down when radio is turned off?  If it does go down that way then it's only the switch.  If not, it's either a stuck mast or burnt circuit (due to stuck mast, for example).  Yes, the circuit board may burn one direction while the other still works.  Mine (87

300SDL, W126) went down but not up.  I replaced the circuit board from another assembly off a W201 and fixed it. Since it can go up, I would remove the mast to test if it slides in and out easily.  It should.  Try lubricate slightly but don't use motor oil which attracts dirt after a while and jams the mast. To remove the mast, loose the base (of mast, just on top of the grommet) then operate the antenna to go up and at the same time slide the mast out (sounds like two man job, right?). If the mast is OK, then it's time for another motor assembly.   Joe Liu wrote: How do I check if it is the antenna motor or if it is the mast ?   The mast was replaced once. This is on a 1998 S500. Best Regards Joe