lexus_newbie

I know there will be other guides on here but i just thought i would share my knowledge what there is of it from installing a sub. I have always thought the IS had a good sound system but just lacked a bit of bass so i decided i wanted a sub. However i wanted to keep the OEM head unit because i like the way it looks and i didnt want to spoil the look of the dash. I know many of you will disagree and say that aftermarket ones look and sound better but i really do like the car to have a uniform look.

Anyway first thing was to find a sub with an amp i didnt want to get a driver then a box and an amp far to complicated for me i mean i dont really know that much about it. So anyway i went to hlafords to have a look and i found one there that had an amp and could take a hi input which means that i could take the amplifed feed from the current speakers in the car and use that as the line in for the amp. This is far easier as you will see as it means you do not need to fit cross overs and stuff like that. Also it ment no alterations were needed to the stereo the car, just what i wanted. Its a vibe sub and is 1200 watts which is more than enough for me.

First thing is first i needed to get a live feed from the battery so i needed to find a way for the cable from the boot the the cabin. Luckly i found a hole at the top left of the boot, this goes through to just behind the back seat. Luckly you can just get to the hole without removing the back seats. as shown below.

Also i needed to feed a smaller switch wire down here aswell this is to switch the amp on an off with the ignition so that it will not drain the batt when the car is off. You can see i have used an earth cable and you may think this to be madness but there is method and it has a good power rating more than enough for the sub. I then fed this wire underneath the trim on the sills of the doors as shown here.

Then i needed to take the front corrner panel under the dash off. The first thing to do is to take the fuse cover plate off of it. You just need to pull it off from the top.

Then there is a final plastic bolt on the firewall that holds it this should twist and pull off also you must make sure that the sill trim is off aswell to remove it.

Next thing to do was take the smaller switch wire to the cig lighter as i knew this was switched with the ignition from installing a parrot kit and a road angle. Anyway i took the wire up through the dash behind the glove box and you can see i have cabled tied it to another loom to keep it out of the way.

I used a splice to connect it to the pink wire on the cig lighter but excuse my photo its not very good as i have so manny devices using this supply. Do not overload this and do not power the sub from this as it is only a 15amp supply.

The next task was the one i was dreading getting the power cable through the firewall into the engine bay. As it turns out it wasnt so bad and this is where the madness of using an earth cable comes in. The earth cable is stiff and made it far easier to push through. Anyway i found the rubber grommet where loads of other wires on the car come through. To get the cable through i taped the cable to an old wire coat hangger which i cut into a rod. I forced this trough the rubber grommet and by doing this it makes a great tight seal around the wire so no water can get in. This is quite a fiddely job so be paitent. I have taken the best photos i could but tricky in these spaces.

After doing this i just wedged it behind the batt and round to the positive terminal. I used a c clip to attach to the terminal. I would advised you that if you use an earth cable it is a good idea to wrap it in red tape at either end which yes i still have to do.

I then needed to take the source for the sub from the rear speakers. Luckly the are very easy to get to in the boot as the are on the parcel shelf. I had to cut away some of the sleeve around the wires as i needed the splice both of them as shown in the pic. Make sure you keep note on the polarity it must be correct for the sub to work.

As you can see i have tapped up all the wires just trying to make it neat and i dont want them hanging down and getting caught in the boot hinges. I did this for both speakers.

I now had all the wires sorted appart from the negative supply which i will get onto later. Anyway i connected it all to the right places as stated on the amp. I used velcro patches to hold the sub in place and it has stayed even though belive me i do chuck the car into the corners. well you have to with a car like the is hehe.

After its all connected listen to your efforts making sure it is all working and you have the levels right then go ahead a velcro it all down.

And as you can see all is normal inside!

Going back to the negative or earth supply i used the chassis as it is all earthed (connected to the negative terminal on the batt ). I connected the lead again using a c clip on a bolt in the boot that holds the sat nav drive in place but i think this is where i have goone wrong. I dont think it is a good earth as when you really turn it up the lights dim with the music. I think i will try running an earth cable directly to the negative terminal on the battery maybe this will help.

Anyway i hope this little guide helped i know its not the best and i dont really know what im doing but i just thought i would share what i have learnt. And all you guys are great on here i always read through the stuff on here which is so helpful and i wanted to contribute to it.

Hi Andrew,

Maybe a silly question but I'm not the most handy of persons.

I'm trying to do the same (ie add a sub) but cant figure out how to gain access to the cigarette lighter pink wire? Do you have have to remove any of the facia bits? You say you ran the smaller wire up through the dash behind the glove box.... but from there I am lost as I see no way of getting to the lighte insides without removing bits of facia or center console.

Any tips welcome.

Found it via google. Was searching for help on the famous Error3.