It is definitely the season for this problem. My '94 405 estate has started the clicking too. Like Bob I have located the clicking motor (small black box) and also like Bob I can't see any easy way to get to it.
I've searched previous posts which all seem to say "it's very difficult to get to, but can be done". I would be really grateful if someone could give some hints as to how to get to this motor to try to attempt a repair.
If I really can't get to it I guess I'll be cutting the cable like Bob did.
Ed