2002 Non-Bose AMP BYPASS INSTRUCTIONS FOR DUMMIES (Like Me!)

STEP 1:
Buy This Harness Assembly on Ebay or Amazon: Scosche GM04B OR METRA 70-2002



STEP 2:
Take needle nose pliers and pull out ALL wires (pin connected to each wire) should pull out easily

STEP 3:
Re-insert wires from this harness like this. (perfect photos borrowed from Javvy)

IMPORTANT: when you push the wires back in the pins will only be exposed half way. You must use your needle nose pliers and gently pull each pin so they lock into place in their full extended position.

You will end up with 1 extra wire....good thing...I broke 1 and used a different color. Color does not matter...just position and proper pairing to it's corresponding wire.

Pair and tape/wire nut bare ends like this:


Empty your glove box and open it all the way to expose the amplifier and unplug ONLY THE BOTTOM HARNESS like this:


You will NOT be plugging your new cable into the amplifier. Plug your newly made harness into the now exposed harness with the blue clip and lock into place.

There is NOTHING more or less about this...I did this with needlenose pliers and wire nuts (you can tape them well too if you don't have wire nuts).

A shout out to JAVVY who found the BEST WAY to communicate this now EASY project! 

Comments...

NEVER USE WIRE NUTS IN A VEHICLE!!!!

You should never use "T-Taps" or other similar connectors either except for temporary use only.

These types of connectors and especially wire nuts make a very simple and not very robust mechanical connection and WILL EVENTUALLY WORK FREE.

Another big no no is to just twist wires together. They too will come apart and is highly unacceptable.

The "LEAST" acceptable method for connection is crimping. A Crimp makes an actual mechanical connection but one that, if done properly, should maintain a long life and not pull free. It also minimizes the resistance between wires it it connected to.

The next "best" way to connect two wires together is to solder them. With a solder connection you actually change the chemistry of the connection and make a connection that will never come apart. The only issues with Soldering is that it can make the wire connection easier to break if you don't do it well and there MAY be a slight increase in resistance in the wire at the connection because you changed the wire chemically.

The BEST way the majority will be able to make connections is to first Crimp and then Solder the connection. This gives the benefits of a crimp which actually connects the copper to copper (Or copper to connector to copper) which minimizes the resistance. The Soldering insures that the connection will never pull apart.

GM Up fitters guide only suggests the Crimp then Solder  method but if you can't crimp for some reason soldering is the next best connection because it won't pull apart.

GM will actually weld the wires together with a spot welding mechanism but this method is not accessible for most people.

As to protecting the wiring... Heat shrink tubing is the preferred method because it never comes off or over time lose its glue and fall off like tape can. Electrical tape can be used to protect connections when it is not possible to use heat shrink tubing.

Scotch +33 is the best tape to use. Scott +88 is the same but thicker and can also be used. Other brand or models of tape are cheaper but you get what you pay for. I have pulled apart wires after 10 years with +33 and they did not want to come apart...

If you do this amp bypass I would suggest getting a soldering iron, some heat shrink tubing and intertwine the  wires together, solder them and protect with heat shrink tubing.  You CAN also crimp the connection prior to soldering them but I have found in this sort of application Soldering works fine on its own.

Just so I am clear.. There is NO application in a vehicle that wire nuts are suggested or safe...

Ideally I would agree...I would venture to guess that a large percentage of folks that performed this bypass used a wire nut or tape to do this.  I was looking for quick and easy without the need for going out and buying soldering gear.

Mine went together very nicely and is working perfectly now. I will give a heads up if/when it fails.

I'm curious about the others who used wire nuts or tape. How are they holding out?
Absolutely no disrespect to redheadedrod! Thanks for the reply! 

Those look like crimp connectors. You had to crimp them on didn't you? Not twist them on?


If you use the Metra 70-2021, you don't have to do any cutting, splicing or soldering.

You just have to re-pin one side to the correct configuration.

Hi Randy,

Saw the 70-2021 connector after I purchased the 2020....I liked Javvy's photos that allowed me to view exactly what to do on the 70-2020....Is there also a closeup available of how the 70-2021 is wired?  Thanks for the input!

Pardon me....I purchased the 70-2002 (not 2020!)

You wire it the same way... Just move one side...

My 02 av I just bought none of the right side speakers work so I bought them extra 70-2021 wired it exactly the way it's shown and plugged it in and no sound at all please help

The speakers themselves may be bad or maybe the balance is turned to the left side.. You may need to test the right side with a good speaker to may sure there is output from the right channel..

or maybe the radio is bad. swap wires Left to right at first place you can behind radio.

IF problem stays then speakers and or wiring needs checking.
IF problem moves then radio is crap.

But the bypass took the sound from the left side but looks like speakers are newer but I will check

Thank you for solving my problem. Used the 70-2002 setup to bypass the amp and it worked.

Prejake20
Is the metra 70-2002 for the avalanche or is it just for the Monte Carlo?

It's originally made for the Monte Carlo but all you have to do is re-pin it and it works for the Avalanche... But if you look at the Metra catalog, they now show a by-pass harness for the Avalanche PN 70-2054... So be the first to review it..

Thanks for the reply. Once I get it, is it just plug&play or do I need to repin it?