My quess is that it automaticaly eject a tape when it's finished.
The problem would be something is jammed in the mechanism that prevent the tape from moving.
It can be the result of a jammed/deffective cassete.
Try with another one.
May need some cleaning or there is a broken piece somewhere.
Electro
May 2013
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix in-car audio.