Note: All photos below show the Right Hand Drive installation. I obtained a piece of dash frame from a wrecking yard and removed glovebox for photo clarity only. Neither of these parts need to be removed from the vehicle for actual installation!
Remove six screws securing glovebox to the dash frame. There are three screws along the bottom and three inside along the top of the inner liner when you open the glovebox door. There is also seventh screw hidden under the centre console. This does not have to be removed.
The glovebox can be pulled away from the dash frame sufficiently to drill the required extra hole in the dash frame.
Carefully measure the location of the mounting hole as per photos below.
This location has been carefully selected to give best lighting effect and clear all under dash obstructions.
If you wish, this bracket can be installed anywhere along the lower passenger dash frame piece, bearing in mind the clearance to the climatronic airbox etc in that area.
Right Hand Drive cars:
This is how I actually marked and drilled the hole.
Put some tape in approximate location and carefully measure and mark the hole position:
I used an awl to mark the hole for the drill bit:
Drill final hole. I put a piece of vacuum hose over the drill bit leaving only about 10 mm of drill tip sticking out of the end. This stops the drill bit from breaking through the hole suddenly and possibly inadvertently drilling a hole in something else as well!:
Left Hand Drive cars use mirror imaged views of above.
Install spring clip onto the new bracket as per photo:
Fit light into bracket. Note that the light needs to to clipped in as per the photo with the plug towards the centre of car. If installed the other way around the plug will hit on the lower A-pillar trim.
When light is mounted in bracket, simply use torx screw and secure the bracket to the rear of the dash support frame. The bracket sits behind the dash frame in the position shown in the photos below:
Bracket and light mounted in car:
You will note that when the glovebox is secured to the frame that there is a sufficient void under the glovebox trim to allow for clearance of this new torx screw:
Final position of the light when the glovebox trim is in place:
The effect at night with the 8J0 947 409 LED fitted: