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W124 DIY Audio Install


Guest benzw124

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Guest benzw124

Hi everyone,

My car has been leaking quite badly over the past month or so with all the rain and I decided to gut most of the interior to chase the leak and solve it once and for all. I also took the opportunity to soundproof most of the floor pan and do up the audio system since everything was out already. This DIY is probably not for the faint of heart and you will need lots of patience plus space to finish the job. An extra pair of hands will also come in handy but its mostly easy to do. Having some background in home audio installs and wiring will also come in handy here. I took nearly a month to put everything back together as the leak although bad, was nearly impossible to find. I drove my car without carpets and passenger seats for the entire period. However, if you just did the audio install plus sound proofing, I estimate about 3 days of work to finish everything. Before we start, here are the tools that you will need.

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1) Various sizes of plus and minus screw drivers

2) A ratchet and socket set with an extension bar. You will need 8mm to 15mm sockets. Just get a cheap $30 set from Mustafa.

3) You will also need 8/9mm and 10/11mm offset wrenches

4) Speaker,RCA cables and an amplifier install kit with an 8 guage wire kit at least and 0 guage if you want to run 2 or more amps. (eBay/SLT) I used a total of 3 RCA cables and 5 speaker cables. 2 speaker cables ran up alongside the RCA cables to the front while the other 3 were for the rear speaker and subwoofer. Adjust what you need according to your set up. I also used shielded cables for everything as I ran everything on one side. The pros will run power cables on one side and signal cables on the other. You will also need to run a remote wire along to your amp to turn it off and on accordingly.

5) 4 inch Speakers if you are not using your current ones and a subwoofer.

6) 5 Channel Amp

7) Headunit (I used an alpine CDA 117 and routed my iPod into the glove box)

8) Black sound proofing bitumen sheets from this local guy selling on his blog. (http://bitumensheets.blogspot.com/)

9) A super bright torch light (optional but handy)

Step 1

So the first thing you will need to do is figure out where to run your power cable. You will need to pull this plastic piece out and I used the stock grommets behind the battery compartment and shove a few inches of wire in it. You should also figure out where to mount your fuse holder and make sure its not too far away from the battery. I wired mine in about a foot from the battery and mounted the fuse holder to a plastic holder in the battery compartment. Be careful where you screw as all the electronic components are in this compartment as well and you don't want to destroy them. You can also remove the battery temporarily from its holder to gain more access to do the work. At this stage, leave the wire DISCONNECTED from the battery and tuck it away from the positive terminal for now.

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Step 2

Remove the glove box. You have to remove the 2 screws that hold the latch in and unclip the small round clips located all around the edge of the glove box. You use a small flat head screw driver and pry the center portion of the clip out first before removing the base. There are 7 such round clips in total. Lastly, remove the light which simply just pulls out from the front and then disconnect the power wire. The glove box will now be free to slide out from its holder.

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Step 3

Find your power cable that you shoved through the grommet behind the glove box and pull more of it in. You will then need to remove the kick panel by first removing the carpet door seal and then unscrewing a small screw near the base. Slide the panel out gently towards you and it should unclip from its position. Once done, just snake more wire in and let it follow the original wiring harness there. You should also remove all the carpets and trim below the dash at this stage to gain some space to work. The carpets lift up and out and the black plastic trim unclips from its position and requires some manipulation to come out.

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Step 4

Remove the carpet near the transmission tunnel. Find the small screw near the front and remove it. After which, slide the carpet downwards and away from the trans tunnel to reveal the rear air con ducting. Remove the screw that holds the air con ducting and the rest just slides out in 2 pieces. You can also start sound proofing at this stage. I used one layer on the floors only and 2 nearer the transmission tunnel and fire wall. The bitumen sheets were basically just to replace the sound deadening material that had been destroyed by the water over the years. I did not want to put too much in also as the bitumen sheets are pretty thick and heavy as you can see below. In addition to that, the W124 is already very quiet.

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Step 5

Remove the passenger seat by first, unclipping the trim piece covering the two front bolts. You then use a 10mm off set wrench to unscrew the bolts out. Also remember to unscrew the seat belt holder thingy attached to the transmission tunnel. You should also remove the arm rest first as the seats are heavy and unwieldy to handle so it could get damaged if you don't remove it. Once that is done, remove the door sills by pulling up on them. You can use a long screw driver to help pry them off carefully. Mine were easy to come off as they were missing clips from my previous respray job. Go ahead and remove some of the side carpets as well by pulling out the small white tabs with a pair of pliers.

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Step 6

Remove the B pillar. Unscrew the 2 screws at the base of the B pillar and slide out the plastic piece downwards. Also remove the seat belt attachment point using your socket and ratchet set. You can leave the B pillar hanging from its top clip as you wont need to remove it for this install. However, if you want to re upholster it, the top spring clip just pulls straight out from the metal body. Take note of how the seat belt height adjuster works here as you will need to align it properly to put it back together later. Also unscrew the final piece of the rear aircon duct and you can lift up the carpet now.

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Guest benzw124

Step 7

Remove the rear seat bench and back rest. To remove the bench, locate the 2 spring clips and push them in. The bench should more or less pop up and you can slide it out after that. The rear back rest is a little more complicated and you will need 2 people to get it out. First remove the two 8mm bolts at the base on each side. Use a torch to find them. You will then need to lift the entire back rest upwards to remove them from the hooks. Use some upward force here and be careful not to break anything. Once the seats have been removed, you will find a wiring grommet near the seat belt mechanism and this is where we will push our wires through into the boot. All you wiring should be able to follow the original factory wiring channel unless you are using extremely fat wires for whatever reason.

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Step 8

Remove up-right boot carpet against the fuel tank first. It is held in by 2 hooks at the top and should slide out after unhooking it. You should be able to see your wires through the grommet now. For the side carpet pieces, you have to locate and remove a clip first. It is a round clip similar to the glove box ones and are just below the hinge elbow of the boot lid. Pry them out gently and the rest of the carpet just needs to be man handled out. Tug near the shock towers first to make things easier. I also continued my sound proofing all the way into the boot as I was going to put a small subwoofer in there.

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Step 9

Tidy up your wiring and label them properly. You should also find a place to connect your ground wire. I used one of the mounting points of the fuel tank as my ground to the chassis. You should also start to plan how you are going to mount your amp here. I am going to use my original carpet and put a backing behind them to mount the amp to. Now finish up your sound proofing on the floor and move on the the right side. Its pretty much the mirror image of the left. Remove the trim pieces and drivers seat and sound proof away!

Step 10

Install new head unit. First you have to remove your old one obviously. If you have the keys, you can use them to slide the old unit out. If you don't, you could try just pushing the back of the head unit out since your carpets and air con ducts are already out of the way. The wiring looks daunting but if you do it one at a time and transfer your old harness to the new one, it should be no problem. Use proper connectors and not just tape them in. I recommend paying someone to do this part though as it can be quite complicated, even worse if you do not have the keys to slide the old unit out. Also remember to route your rca cables to the rear of the head unit. I didnt take a picture of how I routed my cables but you just need to follow the original wiring harness under the dash and wire tie your new cables in.

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Step 11

Now its time to do up the new speaker wires. First remove the dash speaker covers by using a small flat head screw driver to pry the trim piece out from the front. Once it unclips out, there are 2 screws that you will need to remove and the grille should come out. Remove your old speakers and fish for the new speaker cables that you routed from the rear. Wire tie them to the original ones so they do not fall back down and connect it up.

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Step 12

Wiring the drivers side speaker cable. Now this part is a real bitch to do. Once you follow the original harness to the rear of the head unit, you will need to fish it on to the drivers side and upwards to where the speedo cable is. Remove the speedo cable from its clip to allow some slack. Now remove your speedometer by pulling it towards you. Use your fingers to grip the flat bottom part and try and slide the speedo cluster towards you. The speedo cluster is held in by friction. Most of the speedos should come out easily as they have been removed many times before and are quite loose by now. If it doesnt, google to find out how to fashion a tool to remove the cluster. From there, use a coat hanger or a stick to fish the speaker wire up. It should be easier to do with two people but I just did it myself with lots of patience and swearing. I chose the same route as the speedo cable as there are many springs and levers that operate the pedals below. I did not want the speaker wire to get stuck in any of these pedal assemblies as it could be rather dangerous while driving. The connections to the amplifier can now be made. Follow the instruction manuals for the amp and head unit. Once you are done with all the wiring, connect the live cable to the positive terminal of your battery and try your system out. Make sure its working correctly before putting everything back together.

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Conclusion

The sound proofing cut sound by about 5-10%. The improvements were noticeable but did not make a huge improvement so you can skip it if you want. I haven't received my amp yet as I ordered it on eBay so I cannot tell you what improvements there are to my audio system. Overall, the project costs about 1k with all the components, tools and cables included so it was really cheap. A similar install plus sound proofing would probably cost your double the amount so it is pretty worth it if you have the time. In doing this project, I also found out the horrendous wiring job that the previous installer did for the PO. Most of the wiring was home extension cord wiring and parts of it had already burned through the insulation due to the heat generated from the high amps going through them. The leak was a blessing in disguise as most of the wires were submerged in water for the past few years and did not have the opportunity to burn the car to the ground. The wires were also not continuous but had many crimp connectors to join them together and they were also not routed in the proper factory wiring channels. Thats all from me for now and feel free to ask any questions.

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Guest benzw124

Thanks for reading guys. Hahah im no pro, but I thought Id let everyone know how much work is involved in a simple audio install and what to look out for when getting our cars fixed up so that we do not get scammed. There are many unscrupulous installers out there who merely want to get your money and do not care about producing quality work. For my car, Im pretty sure the previous owner paid a lot for the install as there was wiring for two amps, a cd changer and even remnants of an old analogue hand phone system in the car. However, everything was wired in so horribly that it became dangerous because the wires were all melted when I took them out as they were not only lacking in-line fuses, but were not the right size to begin with. In fact, they were not even the right cables as they used scrap extension cord wiring! So for all those out there thinking of doing up their ICE, please be cautious and use your eye power to supervise when doing the install. Thanks for reading and glad you guys liked it.

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Guest kepiting1sg

benzw124 wrote:

Thanks for reading guys. Hahah im no pro, but I thought Id let everyone know how much work is involved in a simple audio install and what to look out for when getting our cars fixed up so that we do not get scammed. There are many unscrupulous installers out there who merely want to get your money and do not care about producing quality work. For my car, Im pretty sure the previous owner paid a lot for the install as there was wiring for two amps, a cd changer and even remnants of an old analogue hand phone system in the car. However, everything was wired in so horribly that it became dangerous because the wires were all melted when I took them out as they were not only lacking in-line fuses, but were not the right size to begin with. In fact, they were not even the right cables as they used scrap extension cord wiring! So for all those out there thinking of doing up their ICE, please be cautious and use your eye power to supervise when doing the install. Thanks for reading and glad you guys liked it.

Like to extend a warm :welcome: to our one & only Singapore DIY ICE forum.

http://www.diysingapore.com/forums/

The forum is quite dead at the moment cos lots of car owner got rich & stop DIY ICE.

Pls drop by to the forum ICE Kopi Tiam.

I m the Kopi Tiam towkay there.

My Kopi kia, Loti Kia & Koi Nen Kia all have ran away leaving behind a haunted ICE Kopi Tiam.

See if U can rev up some renew interest there! :hand:

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