Friends, I bought my 323F, 1.5 Glxi, 1998 model just couple of months ago, grater little car. I listen my local radio during driving, not music. Normal operation used to be on turning on radio the aerial come out and when it fully out radio start playing but lately it developed a fault. When I turn radio on aerial come out without any problem but when switch off radio, motor fold aerial down but motor over run now, even I took key out from ignition. It looks like any mechanical switch or gear to turn off the motor not functioning. Your help will much appreciate.

Location of the aerial is at rear wing, can someone kindly guide me that what is the problem and how I can access motor? Can someone also send me a PDF of instructions to access motor or rest of assembly please?