Aftermarket Amp/Sub Install

This How-To can be used for the following:
Single-Din Non-Monsoon
Single-Din Monsoon
Double-Din Non-Monsoon
Double-Din Monsoon

Items needed:
Aftermarket Amp of Choice
A Directed 750D Monoblock amp
was used for this install
Aftermarket Sub(s) of Choice
2 12" JL Audio W3v2 subs
were used for this install
Amp Wiring Kit
A Rockford Fosgate 8 gauge wiring
kit was used for this install
(1) Line Output Converter
This only needs to be used if you are keeping your
Double-Din headunit or your aftermarket headunit doesn't
have RCA outputs.
Otherwise you can purchase the Blaupunkt AUX-IN adapter
that will mate to the back of your Single-Din headunit.
www.continentalimports.com carries them
(1) Box of Wire Taps
Radio Shack #64-3053
Only used if you are using a line output converter.

The very first thing that must be done is the ground should be disconnected from your battery.  This will prevent you from shorting anything out and also prevent you from getting shocked.

The next thing that can be done is the power wire can be ran from the battery to the back of you vehicle.  In order to get the power wire through the car the wire is going to have to be ran through the firewall.  Thanks to VW, there is a grommet in the firewall already from the factory.  It can be located just above the master brake cylinder. 
Note: On 2004+ models, VW started to cover up the grommet with a "carpet-like" material.  It can be pulled back and the grommet will be exposed.

Put the power wire through the firewall making sure it isn't interfering with the gas pedal.  Pull all the wire through so that there is just enough power wire on the battery side.  Run the power wire along side of the center console on the drivers side all the way to the rear of the car. 

At this point you are going to want to know exactly where the amp is going to be mounted.  That way you can cut the power wire to size.  Once you know where the amp is going to be, go ahead and cut the power wire to size, put the proper end on, and connect it to the amp.  You can also run the ground wire for the amp now.  A good ground point is the hold downs in the rear of the car. 

Once the ground is connected to the grounding point you can run the ground wire to the amp and cut to size.  The proper end can be put on now and it can be connected to the amp.

With that done, you can move onto running the speaker wire from the amp to the sub box.  This is a fairly easy process.  Just size the speaker wire from the amp to the sub box, strip the wire, and connect.

The amp is going to have to be turned on when the car is turned on.  Open the fuse box and find fuse 31.  There should not be a fuse installed.  Fuse 31 is powered when the car is turned on. 

A wire will need to be ran from fuse 31 to the rear of the car where the amp is mounted.  The best way to run the wire is starting under the dash.  Feed the wire up from the back of the fuse box under the dash to the front and the fuse box.  Splice the wire into the "Add-A-Circuit" and connect it to fuse 31.  Finish running the wire along the same path that you ran the power wire earlier.  Run it to the amp, put the proper end on, and connect to the amp.

The amp is going to need to be sent an audio signal.  You can now run the RCA cables.  There are three different ways that this can be done.  It all depends on if you are using a stock Monsoon headunit (Single-Din or Double-Din), a stock Non-Monsoon headunit (Single-Din or Double-Din), or an aftermarket headunit.

If you are using a stock Monsoon headunit (Single-Din or Double-Din):
Since the stock Monsoon headunit's don't come with RCA outputs on the back of them, you are going to have to make your own.  A line output converter is going to need to be spliced into the wires at the Monsoon amp in the rear of your vehicle.  Most line output converters come with four wires.  Then there are some that come with five and even six.  Either line output converter will work, you will only be using four of the wires.  The four wires on the line output converter will need to be tapped into the left positive, left negative, right positive, and right negative wires at the Monsoon amp.  Use the red wire taps to tap al four wires.

Monsoon amp grey connector wiring diagram 

14 - Left Rear Positive (+)
15 - Left Rear Negative (-)
17 - Right Rear Negative (-)
18 - Right Rear Positive (+)

Once you have the line output converter tapped in, you can then run the RCA cable from the line output converter to your amp.

If you are using a stock Non-Monsoon headunit (Single-Din or Double-Din):
Since the Non-Monsoon sound system doesn't have an amp where we can tap the line output converter into, we need to tap the line output converter in behind the headunit.

Single-Din Headunit Wiring Diagram 
9 - Right Rear Positive (+)
10 - Right Rear Negative (-)
15 - Left Rear Positive (+)
16 - Left Rear Negative (-)

Non-Monsoon Double-Din Headunit Wiring Diagram 
The following pins are located in connector I
1 - Right Rear Positive (+)
4 - Left Rear Positive (+)
5 - Right Rear Negative (-)
8 - Left Rear Negative (-)

Once you have the line output converter tapped in, you can then run the RCA cable from the line output converter to your amp.  The best way to run the RCA cable is on the passenger side on the side of the center console.  It will be easy to push the RCA cable up under the plastic just like you did on the opposite side with the power wire.

If you are using an aftermarket headunit:
The first thing that you must have is an aftermarket headunit with RCA outputs.  All you are going to need to do is run the RCA cable from the back of your aftermarket headunit to your amp.  The best way to run the RCA cable is on the passenger side on the side of the center console.  It will be easy to push the RCA cable up under the plastic just like you did on the opposite side with the power wire.

Note: NEVER cross the power wire and the RCA cable.  This will cause static across the RCA cable and you will have a bad signal sent to your amp.

Now that you are done running all the wiring the power wire can now be attached to the battery.  Once the power wire in connected to the battery you can then connect the ground to the battery.  Start your vehicle up and test your system to make sure everything is working properly.  If something isn't working, recheck all of your connections.