Smart For Two 450 Coupe...issue with central locking button behind hazard lights

[saxo_29]

Hi all. Hope you are well.

I'm facing a weird issue with my Smart Passion 450 ( 2006) 700cc.
The central locking from key fob works perfectly. When I drive off, the car autolocking activates as it should. So far so good....
The problem appears when I want to unlock the door from the inside so that a passenger can open from the outside after the autolock has activated.
I press the "lock/unlock button on the triangle control panel right behind the hazard lights ( see picture ) , but it does nothing.... whether stopped in neutral, whether just getting into the car... pressing that button does nothing. Has anyone faced something similar or can shed some light as to what to look into? I do suspect the button switch itself but cannot be sure.

 

Thanks