central door locking prob

hi can anyone help when i lock the doors using my key fob on my 96 p38 everything is fine then when im walking away from it say about 20 seconds after ive locked it the locks make a horible clanging sound,nailed it down to the passenger front door any ideas?

the only thing i can think of is after about 20 secs it super locks you Landy, its like a screw that whizzes in when it super locks, if it goes wrong its a pain in the ass to fix it when its broken because the door wont open with the super lock in and activated, so get it sorted now while you can still open the door if i was you

thanks think i will wip that door panel off and have a butchers.

you can get it by just taking the door card out