I've recently purchased the 2018 ST Line X. The owner before me says it had a black box / telematics installed and it has interfered with the auto stop-start. 

The box is supposedly behind the glove box, how do you remove the glove box firstly and secondly has anyone had any experience with removing these black boxes? 

 

Any tips would be appreciated as I'd like to see if the auto stop-start is working properly. Thank you.

The wiring will be different depending on what company fitted it. Some just use a live feed to power the box, where as others are fed from the OBD2 port.

The only reason I can see it messing with the stop/start is if it's constantly draining the battery overnight and needs longer to charge back up again before the start/stop kicks back in.

The glovebox is dead easy to pivot out of the way. Just press the 2 sides inwards and pull open. You're essentially moving the back stops out of the way so it will open beyond the stops.

Obviously never taken the glove box out of a 2018 MK8. Yes squeeze in the sides but prepare to put some brute force behind it, I've taken mine out and it took a awful lot of effort to release the two bungs...thought the damn thing was going to break.  You also have to take the glove box out if you ever need to replace the glove box light bulb...terrible design.

One note...once you have the glove box pivoting forward its removed from the hinges by sliding the hinge pegs out.