Only some speakers are working.

[KerryNeely]

I just got a 2002 Avalanche Z71 and it's in great condition. Only issue currently is the aftermarket radio that was put in seems too ONLY play the music from the front tweeters. I did the AMP Bypass using the Metra plug and still no sound from the rest of the speakers. The headunit looks brand new and was even in Demo mode qhen I got it. Wires look like they are all hooked up right on the back.

So anyone have an idea why the front tweeters ( left and right ) work but nothing else?

 

[Raekal]

Id go into the stereo and make sure all of the balance and tune settings are default, then play around with things to see if you can get any more response from the rest of the setup. I just had looked at a car that had amp hookups in the trunk (OEM stereo) and the drivers side of the car didn't work, but the tweeter buzzed. I changed the L/R balance and by doing so got it to work the way it should at like +3. So i don't know what they did to it, but even the buzzing stopped afterwards.

That said, this is one of those things where the previous owner was having a problem with it and decided to sell it when the stereo didn't fix things. You might have to check the doors to make sure the speakers are hooked up at all and that they haven't been replaced/ broken/ wired incorrectly or missing all together if you cant see though the panel.

The only other thing i can think of is that the 2002 has unique electrical compared to every other model year of avalanche. Im not sure if this extends to the head unit harness. If it is unique, the sterio may have just been the wrong one. But im not a big AV guy, so take all this with a grain of salt.

 

[ygmn]

too many things:
Does radio send output?
are rear speakers any good?
Wire any good all the way...
Radio set up to play from rears?
External amp?

 

[KerryNeely]

Id go into the stereo and make sure all of the balance and tune settings are default, then play around with things to see if you can get any more response from the rest of the setup. I just had looked at a car that had amp hookups in the trunk (OEM stereo) and the drivers side of the car didn't work, but the tweeter buzzed. I changed the L/R balance and by doing so got it to work the way it should at like +3. So i don't know what they did to it, but even the buzzing stopped afterwards.

That said, this is one of those things where the previous owner was having a problem with it and decided to sell it when the stereo didn't fix things. You might have to check the doors to make sure the speakers are hooked up at all and that they haven't been replaced/ broken/ wired incorrectly or missing all together if you cant see though the panel.

The only other thing i can think of is that the 2002 has unique electrical compared to every other model year of avalanche. Im not sure if this extends to the head unit harness. If it is unique, the sterio may have just been the wrong one. But im not a big AV guy, so take all this with a grain of salt.

Yeah the speakers look like they are in there but I will check. Might pull up a Directech schematic and try to figure out the wires and try to splice into them after the plug

The radio is set completely to no equalization. Just weird the tweets work and nothing else

 

[MS03 2500]

They may have added a amp then removed it when they sold it

 

[KerryNeely]

They may have added a amp then removed it when they sold it

I removed the HU and there was no remote wire or RCA attached too the stereo. It would be rare that someone would take all that but leave a new HU. I think today I will open up the amp Bypass on the amp out side where the wires go too the speakers and use a 9v battery too send a pulse threw the wires and see if the speakers respond with a small thump.

The part I got from Metra is supposed to bypass the amp by making the output of the headunit instead connect directly with the output of the amp.

 

[Mik]

I just got a 2002 Avalanche Z71 and it's in great condition. Only issue currently is the aftermarket radio that was put in seems too ONLY play the music from the front tweeters. I did the AMP Bypass using the Metra plug and still no sound from the rest of the speakers. The headunit looks brand new and was even in Demo mode qhen I got it. Wires look like they are all hooked up right on the back.

So anyone have an idea why the front tweeters ( left and right ) work but nothing else?

Get your meter and check resistance to ground on all 8 speaker wires.
check each speaker individually.
no need to go get a wiring diagram if you have metra parts in there they are all EIA wiring coded.
rf grey pair
lf white pair
rr purple pair
lr green pair
A meter is your best friend!

 

[Mik]

I removed the HU and there was no remote wire or RCA attached too the stereo. It would be rare that someone would take all that but leave a new HU. I think today I will open up the amp Bypass on the amp out side where the wires go too the speakers and use a 9v battery too send a pulse threw the wires and see if the speakers respond with a small thump.

The part I got from Metra is supposed to bypass the amp by making the output of the headunit instead connect directly with the output of the amp.

The metra bypass you installed is to avoid feeding the output of the head unit into the Bose amp and creating massive distortion.