Hi all,

I couldn't find a guide for this so here's a step by step of what I did to install a sub in to my 96 x300 with non premium sound system and a factory head unit.

This requires no cables to be run to the head unit and all the cabling is in the boot, which makes it nice and easy!

Now one concern I have with this guide is that I am relying on your radio aerial acting as mine does.
Which means the aerial has to be up when even the head unit is turned on, and not just when the radio is selected on the head unit. I' not sure if this is normal behaviour for the aerial, but that's how mine is.
If anyone has any details on how the aerial should work, please let me know and I'll update this post.

If you're aerial is not up the entire time your head unit is on, then it gets more complex. You'll need to find the remote wire in the CD changer cabling to turn the subs amp on. Which I'm not sure is possible.
Or I guess you could run a remote wire from the head unit, but I don't have any idea on what that wire may look like or if there even is one. I assume so, to turn on the amp for the premium system.

This while process took maybe 2 hours with a bunch of mucking about.

You'll need:
Cable stripper/cutter
5x two way chocolate blocks
About 4m meters of audio cable
A screw driver
A spanner
A thin knife
Electrical Tape
The sub
The amp - with High (speaker) level inputs.
If you don't have High Level Inputs then you'll need a LOC (Line Out Converter) a stereo one.
Heavy Gauge Grounding cable - 1.5 Meter
Heave gauge Power cable - 2 Meter, with inline fuse
Thin remote wire - 2.5 Meter

Steps:

1. Removal all carpet from the boot.

2. Remove spare wheel so you have somewhere to sit.

3. Get in the back seat and pop out the tweeters with your knife, this is only really easy if you have the ones mounted on the parcel tray.

4. Pull the tweeter cable out its full length (about 12cm) and cut the cable in the middle, leaving enough cable on each side (about 4cm) to strip both ends

5. Get a length of speaker cable and cut it to about 2 meters, strip one end.

6. Use the chocolate block to join (tap into) the speaker cable into the tweeter wire, You'll also re-connect the tweeter.
You basically want to take a split of the signal that is going to the tweeter.
From Memory, the coloured cables are the negative so make sure you know which cable you have connected to negative because you'll need to know this is a minute.
I connected the negative jaguar cables to the black on my cable and positive to the white.

7. Push the other end of the speaker cable into the tweeters mounting hole and towards the boot.
It will come out of a black vent looking thing in the boot on the extreme outsides of the boot interior, I had to poke my finger in and hook it out.

8. Repeat for the other tweeter. Pop them both back in when your're done.

9. Now you should have two speaker cables running from the tweeters and into the boot, you can now strip these.
These are you're signal cables.

10. If your sub/amp came with a loom for the HLIs (High Level Inputs) use two more of the chocolate blocks to connect these to the loom, following the labels on the loom.
Making sure that you are connecting the left positive to the left positive and so on.

If you are using a LOC (Line Out Converter) do the same thing but to the LOC wires instead of the loom.
If you can connect the speaker cable directly to the amp I suggest holding off on that until you have done the rest of the cabling.

11. That's your signal wires complete.

12. Next remove a bolt that holds the CD changer in place and connect the ground cable under this bolt. Hopefully your ground cable has a washer like mine did.
Do the bolt back up with the washer in place and make sure the washer has good contact with the bolt. Do not strip the cable yet. Tape the end to be safe.
That's your ground done.

13. Remove the battery floor cover and disconnect the battery fully.

14. Connect you power cable to the positive cable for the battery, I connected straight to the little bolt on the connector.
Make sure you keep the other end of you power cable from any ground on the car or you'll blow your fuse or zap your self.
Do not strip this yet. Tape the end to be safe.

15. Remove the connector from the power aerial on the right hand side of the boot. The cable in the middle is the one you are going to take a split of.
I think its green. Its the one in the middle anyway. If you want to be sure get out your multimeter and take a voltage reading, it should read 12v with the head unit on
and 0v when the head unit is off.

If your aerial is not always up when the head unit is on, regardless of if you have Tape, CD or FM/AM selected then you'll have to find the remote power in the CD changer cable.
Which is alot harder, good luck with that. Please see the note below **

16. Use a chocolate block to take a split of the switched power from the green aerial wire and connect this to your remote wire. Reconnect the power aerial.

17. Strip the end of your remote wire and connect it to the amp, do the same with the speaker cables (or just plug in the HFIs Loom or RCAs from the LOC)

18. Strip the ground cable and connect that to the ground on the amp.

19. Strip the Power cable and connect that to the ground on the Amp.

20. Reconnect the battery and you're done.


Hopefully, Everyone else aerial acts the same as mine, I have a feeling that someone may have reinstalled the head unit and mistakenly connected the aerial to the remote wire rather then the aerial remote wire.
If that's the case it certainly made my life easier :P

**As for getting the remote wire from the CD changer DIN connector, I guess that would require testing the pins on the connector to find the switched power, then opening the connector and identifying the cable connected
to that pin. Then taking a split from that to turn the amp off and on. That's assuming that there even is 12v switch power in there :P

 

Clever! You've got it right. The aerial goes up and stays there no matter what the function of the head unit, as long as it is powered on. For those who won't be using the airwaves (most of us), we could simply borrow the wire from the aerial and so prevent the aerial deploying at all.

Interesting that the tweeters are already tied in with the full-range rear speakers! If it works in your car and sounds good, then we know that the impedance change with another tie-in is ok. Also, I see there is no capacitor on the rear tweeter wires that would filter out the bass. Very nice!

 

Yea it's quite handy!

I ended up disconnecting the rear tweeters as couple of days later as there was way to much treble. (I've installed door speakers with tweeters in them too)

Also a small update. As other people have suggested it's a great idea to remove the rubber cover from the hole that the premium systems sub sits in. It let's the bass in. The boot is very well sealed! I'll edit the above post to add this step and remove the aerial issue.

 

I looked at the wiring diagram for my audio system and yes the mid-bass speaker is on the same circuit as the tweeter so you can use this for the sub.

What an elegant solution.
I have already fitted my sub and the last job was wiring the phono to the head unit, the most difficult job. This method makes it easy. My Amp does have a high level input to be driven from the speaker circuit. It's just the plug is a bit weird.

I am getting an ebay speaker to RCA adaptor to be sure.

And yes the green wire on the electric antenna does power the amp remote. I did all this before i discovered your instructions ;-)

 

OK I decided to use a speaker to phono converter from ebay. I soldered speaker wires to my tweeters and wired them to the level converter. Then phono from that to my amp. I set the amp in mono with low pass filter switched on and adjusted the amps level controls to produce decent undistorted base at loud car volume.


Having got it basically right I can adjust the bass from the head unit by the bass setting and the front rear fade.


Led Zeplin sounds excellent now.


What I will say is you need that boot sub-speaker really loud in order to feel it in the car. I suspect the fuel tank is getting most of it. Anyway it was loud enough that I need to drive to an industrial estate to test it.