The reason I did it this way is that I don't like messing around with the original harnesses like cutting them of incase I need to go back to oem.
Sorry for phone pics and messy trunk aha
Here we go with the trunk. These are the things I used. Change these if needed to suit your needs.

Materials
-Led light strip. Mine was ~5W 3ft/1m long with 30 leds with resistors. If your strip did not come with resister you would need to add them.
-2 butt plugs 12-14ga (all I had was but go according to your wire size you are using)
-2 spade terminals 22-18ga "#6 stud"<-- that size should fit into the harness
-2ft of 18ga wire
-Double sided mounting tape
-Zip ties if needed
-Electrical tape

Tools:
-Pry screwdriver
-Wire cutters
-Side cutters
-Linesman pliers
-Scissors
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0123.jpg
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0124.jpg

Using the pry tool goto your light housing and push in a little and down on the drivers side(passenger side has the harness). It should come down and then disconnect the harness.
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0125.jpg
As you can see I cracked mine a little. NBD you don't need this anymore.
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0126.jpg

Stick up your led strip. Mine came with double sided tape on the back of my strip but it didnt hold itself up so I used my own 3M mounting tape. I cut like 8 x 1 inch long pieces, stuck them on the strip then to the top of my trunk.
Just find a straight line with no obstructions. Doesnt matter if its uneven.

Using the linesmans cut off 1 spade off the spade terminal otherwise that spade with just stick out on the side and thats sketch. Now they fit into the original harness.
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0109.jpg
I then cut about 2 x 1 ft long wires so I can reach my led strip wires. Strip both ends, crimp one side to the 1/2 spade connectors then crimp other side to butt connectors for both neg and pos wire. Crimp butt connectors to led wires.
My led wire came out on the passenger side and theres a hole/tunnel thing to feed the wires back to the harness and plug spades in(switch polarity if it doesn't light up). Tape up the harness and spade connects and stick back up the hole. Use some zip ties if needed.

Heres how mine turned out.
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0115.jpg
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0116.jpg
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0119.jpg
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0120.jpg








Front Map/Dome Light:

Pretty much same deal. I havent finished this yet as its too cold outside. Here is what I have.
Please note I am doing this diy after I removed some stuff.

Remove cover, there is a notch where you can insert a small flat and pry down. Put cover in safe place.
Remove the 2 cross screws in the left and right lights.
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0127.jpg
Take off harness
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0128.jpg
To remove these two wires
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0130.jpg
From this(you can take this out but turning it left if needed)
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0129.jpg
There is a pin/hook thing that keeps the terminal locked in. The pin thing is on the other side where you put the bulb in. So find something small and flat, while pushing inwards, pull the wire out from on top.
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0131.jpg
Next using 2 x female disconnects with a 0.250" tab, you can slip them on to the terminal like this only one way. Use your pliers to squish the disconnects to make them more snug.
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0132.jpg

Take cover off rear view mirror it easier to see where your feeding your wires, just pry from the side facing the front.
Just pull down a little on the headliner and you can feed the wires trough.
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0137.jpg
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0136.jpg
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0138.jpg

Remove the center light bulb hold so you can feed wires though there if you want, you dont have to.
Its just easier if a problem comes up with the connection.
Crimp wires to connector, attach to terminal, wrap in electrical tape, put everything back together.

Mount the leds using double sided mounting tape.
Pull down the headliner and you can tuck the wires in.
Done!

http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0142.jpg
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0144.jpg
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0151.jpg
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0149-1.jpg


I have 20% tinted windows by and they were rolled up.
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0146.jpg
http://i1178.photobucket.com/albums/x365/huangallan1/IMAG0141.jpg

Nice write up. I need to do this, kind of hard to see in the trunk at night with that pissy oem light

that's one seriously well lit trunk haha..

In for the dome light upgrade....

Awesome. Thanks for the write up :tup:
Interested in seeing how the dome light ends up looking.

Updated first post with cabin light strip! Looks even more brighter in real life

Great idea with using spade ends and cutting one of the terminals off.

I did this to my car about a month ago shortly after I lit my footwells. It's so nice to have decent lighting in the trunk!

As for the map light part, doesn't it blind you when you are sitting in it? It looks like something I wouldn't want turned on when I am driving!