Question to those that might know, on the driver's door top (where you stick your elbow when the window is all the way down), by the B pillar there is a little red light!

It comes on when I lock the car. Sometimes it goes off, other times it stays on and when come back to the car 3 hrs+ later, it is still on. I thought it might be something to do with sensing the keyless key, but don't think that's the reason.

There is nothing the owners manual, I just can't understand what it signifies as it's on off randomness as without the key in my pocket, the car remains locked when I try to open it. 

I don't think it is anything to do with FULL or REDUCED Alarm settings as I've tried that to see if that's the cause. 

Any point ters or a justification for the random light operating would be most appreciated.

Cheers

2017 SMax 2.0 TDI 150

Assuming it's the little red led on the top of the drivers door card, it's function is to show the alarm and locking status.

If the vehicle is "dead locked" and the alarm is active then it should flash quite slowly (about once every 4 seconds?)