it is a good upgrade over the original light which in my car,didnt even have map lights!
Step 1: Choosing the Correct Light
The TT lights do not require. trimming so if you are using one, skip the next step.
Step 2: Cutting
Ok, if you are using a Audi A2 light, it will need trimming down, what i done was use measurements from the old light unit and marked a line on the light of where to cut
Remember measure twice, cut once! although you might need to file the edges of the light down to tidy it up and get the fit perfect, i cut it ever so slightly too dig with the dremal and finished it off with a good file
Step 3: Wiring
This is actually quite simple, you will need to cut the plug off the car's roof loom and solder the plug on from the Audi. in the picture you can see how i matched the colours, i believe the roof light wiring colours are the same across the VW group range but if now, you will need to find out which wires are:
door open +ve
permanent live for map light
you will also need to run the grey with blue stripe wire to the back of the headlight switch and solder it to a wire which will be the same colour. Grey with blue stripe is dashboard lighting used on pretty much all VAG vehicles.
the solid brown wire will need earthed to a ground point, i earthed it inside the roof
Step 4: Fitting
the light fits inside the cavity but requires 1 hole drilling for it to be securely mounted, you will need to drill into the light mount in the roof then fit a self tapping screw through the middle hole of the heat shield 'circled in red'
Step 5: Reassambly and Test
refit the bulb and shade, and you are done, make sure the light comes when doors are opened, map lights work and the illumination works with the dashboard lights.
Don't worry if the red doesn't match your interior lighting colour, you can actually take the light units apart and solder in new 3mm LED's of your colour choice !!!