* Torx 20 and 30 screwdriver
Step 1: Get RCA output from Stereo
You need a High Level to Low Level converter (Speaker to RCA). This is available for about $15 from any car audio shop.
On the GTI there is an AMP under the passenger seat under a little plastic cover.
As I am not game to play around with this amp I have decided to grab the outputs from the back of the head unit.
To start take a look at the upper centre air vent (the big one.) You'll notice a small black rectangle sensor; this can be pried off. Remember that although a lot of these parts may seem stiff they are actually quite fragile, so be careful when prying. Use a butter knife to do all the prying for you.
Once you've done this you are free to pry the rest of the vent away. Best way to do this is to use your hand and pull from up from the opening where the sensor belongs.
Now if you look towards the back (closer to the windscreen) of the exposed compartment you'll notice a screw. Use the appropriate torx bit to remove it, then remove the remainder of the vent housing. Again pull from the back as it is levered from the front.
You'll now notice two more screws. These hold down the upper dash cover. Unscrew these (always remember to stow the screws somewhere safe, as these things always go missing in cars - too many nooks and crannies)
Now you can remove the upper dash cover. Lift from the back and unclip the 3 clips on the back, then use a butter knife to leaver out the 2 clips on the lower front points and there is also one in the middle. Then just pull the cover off.
Once you've removed the upper dash cover you'll see two more screws at the top of
the next plate. These hold the lower dash cover in place, remove these as well.
Double check for metal rectangles around where the plate was. You may have been a bit to mean and didn't pop the clips properly. If you see any of these then super glue them back to the plate and let dry.
Remove the four screws that hold the head unit in place, so that you can bring the HU forward.
YAY. finally we did it. Now comes the fun part.
Below is the wiring diagram for this HU. I have highlighted the wires we need to tap.
Generally I cut the wires then crimp some socket connections at the end of them.
This makes removal, replacement, etc easily. However the wires are all very tight
and wrapped up so I decided to expose the wires and then solder a tap wire off them.
Make sure that you clean up all your joins with some good electrical tape. Don't use the cheap crap stuff. Zip ties are also great for this sort of work.
Done. We now have RCA outputs for the SUB.
Step 2: Get power outputs for other devices (Optional)
I have a Bluetooth car kit that I needed to install also. These kinds of devices require Negative, Positive, and an Auxiliary Positive power which is on when the car is on.
For the first two I got them from the HU during the step above.
Now for the hard one..
There may be better places to grab this input however i decided to go with the cigarette lighter plug.
To do this I needed to remove the DSG gearstick cover thing (pops out quite easily).
You'll then see two silver screws holding the ashtray compartment in place, if you remove these you can pull the compartment out.
Unplug the cable from the cig lighter. After a quick multimeter test, I have determined
that the middle wire is the one we are after.
Now you can do whatever you want with it. I'm making a little switch panel with Sub and Neon switch.
Step 3: Run the power leads
Press the unlock button on your remote, then disconnect the Negative battery terminal.
If you don't unlock your car first you get a nice alarm siren screaming at you..
(found that out the hard way)
Behind it there is a wiring loom running into the car.
Snip one off and run your cable in from there. (Yes I know it is blurry)
You have to remove the fuse box lid. Under it there is a nice power rail which you
can tap straight off.
Ok we have fed the power cable into the cabin, now you have to pull the passenger
side door trim up. first insert a flathead screwdriver under the trim, lift it up
just enough to get your fingers in. Then look for the pins holding the trim on.
Get a big flat head screwdriver and leaver under the pins. Continue dong this all
the way along the trim.
The whole sill is one piece from front to back so just follow it down to the back seat.
Run the Power cables down the passenger side of your car and the Audio cables down the driver's side. This is so there is no interference in your signal.
Woohoo. We have the cables coming into the boot.
Step 3: Install and Secure the Sub
Wire up your amp and sub using the wires we have feed from the above steps. This is an old sub/amp unit from my previous car. Looks crap but it pumps out a wallop.
I used the metal anchor points (just behind my sub) for the negative point. You could pull the seat up and see the seatbelt bolts. These are also good grounds but you need a large triple square bit to get them out.
There are some nice anchor points around the boot. Best off using them. I just used those stretchy things. Seem to work well.