How to Bypass the Amp in a 2004 Impala




Introduction: How to Bypass the Amp in a 2004 Impala

About: Hi All! I like to learn, Period. It does not matter what it is. I then try to pass any and all knowledge that I find and learn to all of you. Which is why this site is perfect for doing so!

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:


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:

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:

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:

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)
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:

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:

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)



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:

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:

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

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    7 months ago

    It seems like the connector labeling is just as bad as it is on the 2000 Impala. All of the pins are listed as outputs which is silly.

    It looks like the front tweeters are fed by a separate amplifier. You have 6 wires for say right front, so the amp must do an electronic crossover for the front tweeters with one differential input and two differential outputs.

    This amp appears different between the 2000-2001 models because I'm assuming the radio is putting out speaker outputs at all times. In the 2000-2001 the head unit is "told" to put out pre-amp signals by a 27K|47-pf capacitor to ground on the AMP SENSE input that is present on the 2000-2001 amp.


    8 months ago

    I have 2000 Chevy impala and my factory or stock radio keeps making a popping sound when everything is off and I accidentally hit my factory amp while taking out my subwoofer box out my trunk so now my back rear speakers dont work or no sound coming from the two speakers but front speakers still work with sound. I need help to how to fix the factory amp or is there a way to get it to work. I wanna try to it with everything orginally stock SYSTEM


    Reply 7 months ago

    I lost a really long post that would have really helped you. I don't feel like doing it over again right now.

    I made a very long post and lost it "Something went wrong". Unverified email. it asked me to change my password, so it's stupid.

    The essence of my post.
    Get yourself a Metra bypass harness for now. The one I got flipped the
    front and rear speakers. It was wired wrong. Metra didn't care. I
    think they all are.

    2. Turn off the problematic speakers via fade/balance in the radio. I suspect there will be no change.

    amps contain a low pass filter and a notch filter for each speaker. It
    probably reduces output at the cabin resonant frequency.

    4. it's likely the amp. Jumping the vehicle has a tendency to make the amp die.

    The front speakers are likely to die first. They get scratchy. The
    left front speaker does the chimes. I replaced mine with Rockford
    Fosgate and a speaker harness connector. I used a Dremel tool to fix
    the mounting holes and installed a baffle to keep out water. The door
    panel fasteners are basically one-time use.

    6. At least pull the connectors on the amp and re-seat them.

    7. I am in the process of making a harness to be able to put the amps on the bench.
    When I'm done, I'll probably have the ability to have an instantaneous snapshot of all 4 channels using 4 different frequencies.

    8. There are 3 part numbers for the 2000-2001 and the *548 is reported to be the best sounding.

    9. A service manual is available for the 2000-2001 amplifier on the web.

    10. I think I know why the amps are dying and I think I can fix the problem.

    The amp can be removed from the trunk side by cutting the x-mas tree
    fasteners and replacing them. I have not found 1/8" thick felt washers,
    but I have found 1/4" ones that can be cut in half.

    12. The amp
    tells the radio to put out line level outputs with a 27K||470pf network
    to ground on amp-sense. The head unit can drive the speakers directly,

    On one working amp, I have made two of the preventative fixes. I'm not
    going to install that amp until I make a small PCB which can be
    installed where an unpopulated IC goes. At this point in time, it may
    include some test points too that would be accessible via a connector as
    well as the components necessary for the fix. I'm going to etch the
    first board by hand.

    14. I may offer a kit of parts and I might
    offer repair and the installation of the fix. I don;t know. I have a
    working *548, one with the left front channel bad and one that won't
    turn on. I have 2 or 3 of the other models that won't turn on. One I
    fixed and after a jump, it died again. I also have a 2002+ model amp
    with the 12-way connector.

    FWIW: I did manage to replace the
    trunk and interior lights with LED replacements. You have to put a
    resistor in parallel with the trunk light or very weird things happen.\


    Reply 8 months ago

    you would have to start by looking at your amp, depending on how hard you hit it you could have broken something in there. If so you would need to buy a replacement. next check where you hit around, might have broken a wire somewhere.


    Question 2 years ago on Step 5

    I'm sure I'm just an idiot here but I have connected on my wires but I have two black ones coming from the bigger of the two connectors I have one black one on the smaller one. I'm just afraid I'm going to mess it up can you help me


    Answer 2 years ago

    Both blacks on the bigger connector SHOULD be the ground wires, the other black wire on the smaller connector should be for the LEFT FRONT TWEETER POSITIVE(+) WIRE. I hope you also made sure that you have the BOSE stock amp in your car correct?


    5 years ago

    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


    Reply 2 years ago

    On the passenger side behind the passenger seat there is the wire harness to the amp, the wire maybe corroded out and needs to be spliced, it is one orange wire going into two orange wires that powers up you amp, that is your problem, I fixed mine yesterday


    Reply 5 years ago

    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.


    4 years ago

    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.?


    Reply 4 years ago

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


    4 years ago

    #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.


    Reply 4 years ago

    #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


    4 years ago

    Thank you for the information very helpful


    5 years ago

    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


    5 years ago



    5 years ago

    What is the part number for the stereo replacement interface?


    6 years ago

    Soni connect A1 to B1 or A1 to B12?


    Reply 6 years ago on Introduction

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


    Reply 5 years ago on Introduction

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