Upper Electric Module
 

On both S60s I've owned this always falls out of the roof, what the best way of securing it?

There should be 2 screws in the light that hold the unit to the roof.

Nope only friction fit on both cars

Had mine off enough, there should be 2x torxs screws in the light under the cover. If it wasn’t solid the mirror would keep falling down.

Ah right I'm on about the thing near the sunroof in the centre of the roof? Square plastic. I searched for central electric module and it looked like a fuse board so assumed it was the upper module

Mine drops down too, but I don't have a printed circuitboard in there. Only saw what the empty cable is supposed to lead to when I saw a wrecked V70 in the junkyard with the circuitboard hanging down.

It is a question of bending the retainingclips in the right angle. Most plastic can be somewhat molded somewhat when you keep it under hot running water and bend it carefully. I don't recall what it looks like in the rooflining.

But that's theory: I've done it with many things, but not this square plasstic thing in my roof.

It's the mass movement sensor and needs to be stationary and needs to be properly placed when alarm is activated (if you push it up and it falls while activated, it will give false alarm and when tilted, it won't guard the inside of the car correctly. Thieves know it and after an incident so do I.

ah ok marvin thanks for that, I assumed it was the sensor for the remote fob.

I'll do what I did on the last one - affix a magnet and stick it to ceiling