A basic guide on replacing the third LED brake light which is found on the boot/trunk lid.
The new part:
Part no: # A2118201256
Cost: £71.80 inc VAT (UK)
If you look at the third brake light unit, you'll notice it comes in two parts.
1. A black housing which has the PCB and the LEDs itself. This has two sliding black tabs which help it hook onto the red plastic bit. This is refered throughout the guide as black housing
2. The outer red plastic bit (the visible part of the unit from outside the car). On the underside, it has grey plastic tabs which fit into the black housing. This is refered throughout the guide as red plastic bit
1. Open the boot/trunk lid.
2. Remove the Warning Triangle from it's braket.
3. Using a flathead screwdriver, pull out the small grommet pins then the grommets itself. Four in total, check picture for locations.
4. Using a flathead screwdriver (narrow head) or an allen key of the correct size, unscrew the six screws holding the plastic trim along the bottom of the boot/trunk lid. Six screws in total, check picture for locations. Remove the plastic trim.
5. Once the grommets (four) and screws (six) have been removed, unhook the carpet from where the plastic was located and pull back the carpet until you can see the third brake light housing at the top corner. You may need to unclip the power to the boot/trunk light to allow you to do this.
6. The image above is what you should see. There are two sliding tabs which need to be moved in the directions shown which will then unhook the black housing. Note: The left tab has been moved across and is unhooked. The right tab is in it's original position and still needs to be slid across. Now, slide the two tabs to unhook them. You will need to use moderate pressure, but they should move easily enough.
7. Here is the tricky bit. Once the two sliding tabs have been unhooked, using a kind of forward and back wiggling motion loosen the black housing. If you notice, the hole you're working through is smaller than the length of the housing. What you need to do is to push the black housing to the left, then once the right side is clear of the hole's edge on the right, pull it out. Pull out the black housing so you can see the power plug. Unclip the power plug (picture below) then the black housing will be free.
--- NOTE ---
Now at this point, I tried to install the new black housing to finish the job, but because of the tight space, there was no way for me to get the grey plastic tabs (from the red plastic bit of the light) into the slits in the black housing. I had no choice but to remove the red plastic bit.
--- END NOTE ---
8. Now working on the outside of the boot/trunk lid, using a flathead screwdriver, lift up the red light from it's recess and slowly pull it out of the hole. There is a sticky foam strip which holds the part in place. If you can, pull that out and then the light should pull out with moderate effort. I broke my light as you can see. Since you have a new red light, you may as well snap yours apart (much easier!). See below.
9. Using white spirit and a cloth, wipe the grime left by dirt and glue from the recess. Otherwise the new sticky foam strip may not make a good contact.
10. Open your new part box and remove the new third brake light unit. Seperate the black housing and the red light bit from each other. Working back inside the boot/trunk lid, connect the power plug to the black housing unit.
11. Carefully put the left side of the black housing back inside the hole and position it as far left as you can until the right side can pop inside the hole. Then move the black housing to the centre of the hole.
12. Remove the backing paper from the sticky foam strip found on the underside of the red light bit.
13. Push the new red light bit through the hole on the outside of the car and press firmly into the recess.
15. Push the black housing onto the grey plastic tabs and then slide the black plastic tabs in the opposite directions as previously mentioned above. This should now lock the black housing in place. Once again, a moderate amount of force will be needed. You'll hear a 'click' for each tab once it's in place.
16. If you unplugged the boot/trunk light, reconnect it now.
17. Unfold the carpet back to how it should be and work backwards from instructions 5 to 1.
18. Check that you have no left over screws, grommets and grommet pins.
19. Close the boot/trunk lid and test your lights.
20. Victory dance.
Hopefully this will be of help to some of you.