Introduction: How to Bypass the Amp in a 2004 Impala

Picture of How to Bypass the Amp in a 2004 Impala

If you are like me and hate being told that something is impossible to do and you own a 2004 Chevy Impala nad your stock Radio keeps shutting itself off at random when you are driving and turns on after you shut your car off then this instructable is for you .

This instructable is for people who own a 04 impala with a BOSE FACTORY AMP , since Chevy used several different vendors for the amps im not sure if the wiring will be the same.

Step 1:

THINGS YOU WILL NEED

16 Wire nuts (more if you plan on trying to get the factory tweeters to work)

Wire cutters/strippers

Eletrical tape

The ability to crawl into your trunk and stay there for a few mins

Step 2:

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The first thing you need to do is open the trunk of your car then DISCONNECT the battery from your car (if you don't and get zapped do not blame me)

Next unplug both harnesses that are conected to your cars AMP (They will have a tab on the top of them that you need to press down on to get them out)



Step 3:

Now here comes the fun part

You can choose to do this several (or any) way that you want. I just took the most direct way of accomplishing this task.

Here is my way.

crawl into your trunk, pull the back seats down if you need to have more room to work with and get your wire cutter/strippers and wire nuts ready

Step 4:

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I found a wiring diagram online so it will a little Easy to follow. IF you have a 2000-2002 the wire diagram is different , sorry.

you will be basically be bridging or connecting the wires from the first harness to the second harness to preform this bypass.

Step 5:

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Ths is the order of wires to splice together / bridge

2002-2005 Don't follow the same amp wiring as the 2000-2001

You need to follow this pinout:

A9 -> C
A10 -> D-(D=WHITE, not GRAY)
A11 -> E (E=Lt blue w Black)
A12 -> F (F=Lt Green w BLACK)

B9 -> K (TAN wire, closest to M)
B10 -> J (TAN wire, FURTHEST FROM M)
B11 -> H (H= Dark Green w WHITE)---> SKIP THIS ONE AND SAVE IT FOR LAST
B12 -> G (G= Dark Blue w White)

You can't connect the front tweeter at the amp unless you add a crossover (So I have been told, I did not try it, just getting my radio to work was enough for me)

So basically you go to the first harness and find A9, which is the LIGHT BLUE wire on this harness, cut the wire, strip it, and then do the same to the RED wire on the second harness. Then put the tow togehter in you wire nut and twist to join.

Repeat this process for all of the steps untill you get to B11

Note on the B11 WIre
This will be LIGHT GREEN, but the OTHER WIRE ON THE OTHER HARNESS might be several different colors. this cart says that it is supposed to be DARK GREEN WITH A WHITE STRIPE.....MINE WAS JUST DARK GREEN

If you get to this step and are wondering what wire to cut/splice/join, look at the wiring chart for that harness, there should only be a few uncut wires left on it, 4 mabye more. go by the chart and match the wire colors up, IF yours is not DARK GREEN WITH A WHITE STRIPE it should be the only other color that is not on the chart, and that is not cut.

Step 6:

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once you are done (if you just did it the easy way like I did ) then both of your harnesses that plugged into your FACTORY AMP will look like this.

now pull out your electrical tape, wrap all of this mess back up, tuck it into a empty cavity in your trunk

Get out of your trunk, reconnect your battery, and you can now enjoy your factory radio and know that it will never shut off at random again.

A note on further upgrades to your cars sound system

Now that you have bypassed your cars amp, you do not need to go out and buy a $100 plus harness to do so if you want to add an aftermarket radio, just the $32 harness with all of the chime features at Walmart

The same will go for adding in an aftermarket amp, since you bypassed the factory one you can add an aftermarket one and use the battery power, grounds, and tweeter wires left over from these harnesses

You can also see if you splice in the tweeter wires to their corresponding wires on the harness (I.E LEFT SPEAKER + tweeter wire to LEFT + speaker wire. I did not try this because getting my radio to just WORK like it is supposed to without spending a couple of hundred bucks is worth it alone.

If anyone does the tweeter splice and or the aftermarket Amp with the rest of the wires please post it on here for all to benefit.

Step 7:

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Ok, I must admit that getting my aftermarket radio to work was a great accomplishment, but I got tired of my stero sounding like crap realy quick. So I tried (and sucessfully completed) the method of intergrating the factory tweeters and reintergrating the factory amp in the system while using a aftermarket stero.

Now as I stated before you can go out and buy a $180+ bypass harness to do this for you, but then you will ot have the use of the amp and tweeters which will result in your music sounding like crap.

so here is what you will need to complete this instructable.

More Wirenuts (you can butsplice, solder, or join them however you like, I was in the trunk of my car doing this and did not want to spend any more time than I had to doing this)

Wire strippers/cutters

Several peices of wire (about 6 or less inches long, stripped on both ends)

Time

Paitence

A Scosche factory stero replacement interface (if you are putting in a aftermarket unit, this needs to be put in to keed the chime features in your car and to keep it from giving you a bunch of diagnostic error codes)

Step 8:

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The first step is to DISCONNECT the car battery, second is to pull your dash out and remove your stock radio, next use your wirenuts to join the aftermarket radio harness to the Scosche factory stero replacement interface, I will not go over this in detail because all of the wires on both the aftermarket stero and Scosche factory stero replacement interface are labeled, and pre stripped, all you have to do is connect them together with your wirenuts, plug in the interface harness with the stock harness and put your new stero back in your car.

Now we have to go back to the wiring diagram that I posted in the earlier steps, go to the smaller harness (there should now only be four or five wires still attached to it) and cut the PURPLE WIRE, this is the wire for the RIGHT FRONT TWETTER NEGATIVE(-) .

Now go back to your joined wires and find the DARK GREEN wire joined to the LIGHT BLUE w BLACK STRIPE WIRE, this the RIGHT FRONT SPEAKER WIRE, you want to JOIN THESE WIRES TOGETHER ALONG WITH ANOTHER STRIP OF WIRE LONG ENOUGH TO REACH THE  CUT DARK GREEN WIRE ON THE BIG HARNESS. (I used BLACK wire for all of my bridging of the wires back onto the harness so I would not get confused when connecting and reconnecting all of these wires together).

After joining the wires together join the new piece of wire to the wire FROM THE HARNESS, REMEMBER TO MATH THE COLORS!!! THE DARK GREEN WIRE IS NOW CONNTECTED TO SEVERAL WIRES AND BACK TO ITSELF. (We are doing this to reintegrate the AMP BACK into the system along with the factory tweeters, WITHOUT HAVING TO BUY A REALLY EXPENSIVE Harness.

You will do this for the rest if the wires on the small harness, so the next one will be YELLOW WIRE =( LEFT FRONT TWEETER SPEAKER OUTPUT NEGATIVE (-), connect this to the GRAY WIRE THAT IS JOINED TO THE WHITE WIRE, Don’t forget to add another piece of wire to bridge back to the GRAY WIRE on the BIG harness.

Next is the BLACK WIRE (LEFT FRONT TWEETER SPEAKER OUTPUT POSITIVE (+), connect this wire to the  BROWN WIRE that is joined to the DARK BLUE w WHITE STRIPE WIRE, once again do not forget the extra piece of wire that gets connected back to the BROWN WIRE on the BIG HARNESS.

Last, cut the LIGHT GREEN WIRE on the SMALL harness (this should be the LAST WIRE ON THE HARNESS, IF THE WIRE IS NOT LT GREEN, don’t sweat it, it could be several different colors) this wire gets connected to the LIGHT GREEN WIRE that is joined to whatever color wire your harness has for this output, this is for the RIGHT FRONT POSITIVE OUTPUT TWEETERS/SPEAKER circuit, connect the last piece of wire to this and join it back to the LIGHT GREEN WIRE ON THE BIG HARNESS.

This completes the bridging/ reintegration of the factory AMP and TWEETERS to your aftermarket sound system.

Step 9:

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Now you can kiss this small harness goodbye, and your work should look like the third and fourth picture.

Plug the big harness back into the factory AMP

RECONNECT your car battery

Start your car, and test your handywork, you should hear sound right away, if you do congratulations, you did it correctly, if not go back to the wiring diagram and see where you went wrong.

If you did it right, pat yourself on the back again and crack open another cold one, you just saved a ton of money and now have a better radio then the crappy stock unit that uses the factory AMP and Tweeters

Comments

dndworld0805 (author)2016-11-22

I checked and I don't have a short. I'm going to buy some male to male jumper cable. What size should I get, 200mm, 100mm, 50mm, etc.?

mfrontuto (author)dndworld08052017-01-31

whatever gauge wire is on the harness will work (sorry I do not know the gauge of wire)

PaulR238 (author)2016-08-07

#1.) If your radio is cutting off due to the amp, you have a short.
#2.) "You cant connect the front tweeter, or so i was told."? The front tweeter? Really? As if its separate from the door speaker?
#3.) Your wiring diagram is off, and your hand written one is not very intuitive.
Rear Speaker +'s @)are the same on GM, the grounds will be different. Also, in A3 is where the the White wire goes, not B3, and it is NOT Antenna Signal Sensor, but rather ACC Power on.
I just finished my wiring on my Canadian Factory Built 2004 Impala Base 3.4 Police Suspension Package, until i put a digital signal processor in to add back in the lost sound and cancel out/reduce more noise.

mfrontuto (author)PaulR2382016-08-11

#1.) That could also be the case, but I did not have a short, I was rewiring the factory harness to an aftermarket stereo so I did not have to buy an expensive bypass module.
#2.) Yes, The Tweeters have a separate Positive (+) and Negative (-) Wires for each tweeter, I do not know if they are "separate" from the speaker themselves, but they do have "separate" wires
#3.) It was the correct wiring diagram that I found for my car, and I also stated that it could vary. If your car was a cop car previously then it has different parts in it ranging from a larger shorter axle on one side of the vehicle to possible different wiring. As I stated in this instructable If you do not have the 3.4l base (which would include the police model as being different) model then this diagram will be different from what you have

luisg189 (author)2016-06-04

Thank you for the information very helpful

SinclairD1 (author)2015-12-24

Im tried to install a after market stereo and no sound and then i lut orginal back and no sound but power and no chime whats that

mfrontuto (author)SinclairD12015-12-28

not sure, did you cut any wires? is this an 04 impala? is the setup STOCK? if you answer no to any of these I cannot help, sorry. But remember that if it is a 04 Impala, ALL of the chime features, oil sensor functions, and more are in the factory stero, that is one of the reasons that it is still 2 dim instead of just one.

mfrontuto (author)2015-10-02

I do not know . I bought the module at my local Walmart. it will say it is for GM vehicles for a specific year-to a specific year

JuanP43 (author)2015-10-02

GM2000A??

JuanP43 (author)2015-10-02

What is the part number for the stereo replacement interface?

av.rblocka (author)2015-01-20

Soni connect A1 to B1 or A1 to B12?

mfrontuto (author)av.rblocka2015-01-21

A1 should go to B1 as both of these are Ground Cables

NaelynnR (author)mfrontuto2015-09-06

you have to cut these? Im confused. It doesnt say in the intructions.

mfrontuto (author)NaelynnR2015-09-07

it says so in STEP 5.

NaelynnR (author)mfrontuto2015-09-08

I connected a1 to b1 and a3 to b3 and now i have sound but REALLY low sound. So its sounds like the tweeters are not on even worse though. The wires connecting back to the large harness are the same ones that were on originally because of the quick splice.

mfrontuto (author)NaelynnR2015-09-09

If you used quick splices the little plug should NOT be plugged in even
if you did not cut any of the wires, if you did cut the wires then it
should look like STEP 9, where the plug is completely cut off. The
bypass and reintergration takes care of the signals going to and from
the amp via the large plug, if you still have the little connector
plugged in, unplug it, and make sure all of the wires you have togehter
in the quick splices are correct. It should work for you

NaelynnR (author)mfrontuto2015-09-10

Yes the little plug is gone. The original wire from the large is plug is still attached going to the quick splice all the way through. So some quick splices have 2 wires and four have 3 wires because of tweeters. Im thinking maybe I messed up on the tan wires. If 1 color wire is wrong do they all not work or will they sound super muffled? Its either I messed up the colors or I did not reintegrate the tweeter properly. Like I said before I have sound from all the speakers but only if you put your ears to them you can barely hear them. Thanks for your help and time. I really appreciate it.

mfrontuto (author)NaelynnR2015-09-10

if you are having problems using the quick splices I would recommend that you take them all off and try the cutting method that I have done in this instructable, go wire by wire, and it should work for you

NaelynnR (author)mfrontuto2015-09-10

i did that on the front speakers already today with no luck. Do I need to do anything with the white antenna wire?

mfrontuto (author)NaelynnR2015-09-10

no, Please see the diagram on STEP 5, as it shows exactly what wires you will be using to connect to the wires on the other harness

NaelynnR (author)mfrontuto2015-09-11

I have my aftermarket amp hooked up to the remote wire from my aftermarket deck. Do you think that is why I'm only getting low volume? If i remember correctly I only hooked up the remote wire to my amp. I dont remember if you had to connect your aftermarket deck remote wire to the new chime unit.

mfrontuto (author)NaelynnR2015-09-11

Naelynn, if you are using an aftermarket amp this WILL NOT WORK. This instructable is only for the FACTORY amp that came with the car as explained in the beginning of the instructable. Unfortunately I do not know how to do this with an aftermarket amp

NaelynnR (author)mfrontuto2015-09-11

Im only using a mono amp for my 12 in subs not for the 4 speakers.Im going to check tomorrow to see if i spliced in both amp wires to the deck.

mfrontuto (author)NaelynnR2015-09-06

yes, you have to cut and connect almost all of the wires to each other as per the instructions, please be sure to follow the diagram CAREFULLY, if you connect a wrong wire to another it will not work at all. Also this only works for 2002-2005, if most of or all of your wires are different colors, then you need to find its correct diagram so that you can complete this properly

mfrontuto (author)mfrontuto2015-01-21

also is your car 2002-2005? if not this diagram will not work for you

NaelynnR (author)2015-09-11

There are 2 right front (-)....misprint?

mfrontuto (author)2015-09-07

Naelynn, in order for this to work you have to bypass and reintegrate all of the wires in the steps, since you are uisng quick splices you will have the wires that get connected together in the right quick splices . when you do this the signals to the tweeters and amp are being bypassed and reintegrated tricking the system into thinking that you have the stock unit plugged in sending the signals through all of the wires, allowing you to use whatever aftermarket unit you want. You will also have to use a module like the one I have shown or similar so that it sends the right signals to your cars dash/systems or else you will also run into problems

NaelynnR (author)mfrontuto2015-09-08

Thanks again. One question is it ok for the rear speakers to be still connected to the large plug since i used quick splices? Or should I cut the rear speakers off the large plug? So eventually the only wires connected to the big harness is the white remote wire(antenna) and the 4 front speakers for the tweeters? So 5 wires? Hopefully my stupidity will help others.

NaelynnR (author)mfrontuto2015-09-08

I think i get it(hopefully). So If i have the wire(attached to the large plug) still attached to the quick splice i dont need to cut it and run another wire to it from the quick splice bundle. Im hoping that once I connect the power and ground this will work. If not ,Im going to start over. Also i have that gmos-04 system that keep chimes and onstar. I think its the same as yours only retains onstar.

raymond.bennett.549 (author)2015-01-18

Thanks for this post, it helped greatly. I installed a Pioneer FH-X720BT and Kicker replacement 6.5 and 6x9 speakers. After installing them the volume was low and very distorted. I read this post and first tried jumper wires between the two female amp plugs to see if this would solve the problem before going any further. With one speaker jumped it sounded great so i proceeded. I followed the steps in this post with the exception of cutting the wires, instead i used quick splices. I had to use 14-18 ga quick splices since i could not find any 18-22 ga quick spices at any of the auto parts stores nearby. If you do this ensure that the splice blades are completely depressed to ensure the insulation is properly broken on the stock wires due to their small guage. I also jumped the tweeters into the respctive front spaker wire and they work great. Again, thanks for the help, i would have never thought to try bypassing the amp.

Hope you guys see this cause its a little late. I used quick splices on this job like you. I jumped the tweeter and speaker in the same quick splice. So i have the little adapter gone now and only the large plugged in with the other wire jumped in. I did not do the first set of steps because i didnt have to cut the wire. So I figured that i did not need the extra wire to bridge it back to the large adapter. I am getting no sound out of any of my speakers. Do I have to do the initial "round about" before I use my quick splices?

mfrontuto (author)NaelynnR2015-09-06

yes you do, the first step bypasses the amp so that your aftermarket radio will work, and the second step reintergrates the amp so that it does not sound like the volume is on low when it is on HIGH, also as Raymond states you need to make sure that the blades on the quick splices are FULLY DEPRESSED so it fully contacts all of the wires. As I used wire nuts I did not have to worry about that

NaelynnR (author)mfrontuto2015-09-07

I forgot to tell you I bought this

AXXESS GMOS-04 ONSTAR INTERFACE FOR AMPLIFIED GM SYSTEMS

My speakers worked before with my aftermarket deck just low volume and distorted. Before I redo everything I wanted to ask you first.

mfrontuto (author)NaelynnR2015-09-07

my system is non GPS, just the stock, the low volume is because the system has tweeters and the amp that is not registering with your aftermarket unit. The bypass and reintegrating of the amp and tweeters fixes this issue

your welcome, glad I could help

Glad I could be of help. I will soon be replacing the factory speakers on my Impala as well (as they are now 11 years old and do not sound so good). that should be an interesting Instructable for me to make

av.rblocka (author)2015-01-20

I need help...have my radio on and everything...just no soundsmh

oscar.hernandez.142 (author)2015-01-09

My amp doenst work so if i have a powerful aftermarket radio/headunit i could just do steps 1-6 and it should sound alright...correct?

unfortunately no, the speaker setup form the factory utilizes tweeters and without the amp loped back in activating the tweeters your radio will work, but it will sound like the volume was turned way down... that is why when I first did this I reintegrated the amp back in on top of the bypass. so to answer your question YES it will work, but it will sound horrible (the tweeters will not work) if you do not follow all of the steps

I just dont want to use the factory amp because it doesnt work good in the cold the volume is way low so i want my aftermarket radio to power my aftermarket speakers that have tweeters

I just have the stock speakers so I do not know, if you try let us know the results

I replaced all the apeakers though with twitters in the door and deck speakers included

oscar.hernandez.142 (author)2015-01-09

By the way thanks alot for posting this!...this is the only thing i have ever found online about this

I took me a lot of research to find all of this information as well. glad I could help out others

oscar.hernandez.142 (author)2015-01-09

My amp doenst work so if i have a powerful aftermarket radio/headunit i could just do steps 1-6 and it should sound alright...correct?

estay1 (author)2014-12-10

I wanted to thank you for making me the hero of my family we now have a radio again!

mfrontuto (author)estay12014-12-10

you are welcome! glad I could help out someone else with this problem

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