Since owning my 1999 UK Classic, there is a loud buzzing/grinding sound coming from the drivers door when I press the alarm fob to lock the car. It doesn't make the noise when unlocking though.

The alarm flashes the hazards and all doors are locked but when pressing the fob to lock/arm the car it sounds like the central locking motor is overworking and makes like a grinding/buzzing sound. Made me jump the first time lol

I tried replacing the door lock mechanism but that doesn't seem to be the issue. I then found the little black box that pulls the metal rod to engage the central locking, i'm guessing I should replace this but is there a chance that a relay is sticking and forcing this motor to run too long causing the grindy buzzing sound?

 

thats an aftermarket motor to allow a 3rd party alarm to operate the CL.......

 

Cheap enough to replace......

 

Thanks both, the problem escalated from there to the 3rd party alarm control module packing up and completely immobilising the car on my driveway with a window down... So its being ripped out and swapped for a new replacement.

I have ordered a new motor for the door too which I can swap at the same time