Buzzing Noise at Rear Speakers 2007 Tahoe/Suburban

[Manuux96]

Hello everyone,

I’m reaching out from Germany because the community for Suburbans, Tahoes, and Yukons is quite small here. I drive a 2007 Suburban, which is essentially the same as the Tahoe and Yukon, just a bit longer.

I bought the car with an aftermarket radio already installed by the previous owner, and I've been having issues with the sound system ever since. When I turn on the rear seat audio (RSA) controller, the speakers produce a buzzing and humming noise, and the sound is very faint. When I turn off the RSA, the buzzing stops. When the engine speed increases, the noise does not change but remains constant.

I’m trying to troubleshoot without buying a new RSA unit because the shipping costs to Germany are very high. I’d like to know which pins on the connector need to be bridged to bypass the RSA and see if the buzzing comes from the RSA or my CANBUS adapter (PAC RP5-GM31).

Has anyone dealt with a similar issue or can provide a pinout for the RSA connector? Any advice would be greatly appreciated!

Thank you in advance!

 

[Tahoe14]

@Doubeleive

 

[Doubeleive]

Hello everyone,

I’m reaching out from Germany because the community for Suburbans, Tahoes, and Yukons is quite small here. I drive a 2007 Suburban, which is essentially the same as the Tahoe and Yukon, just a bit longer.

I bought the car with an aftermarket radio already installed by the previous owner, and I've been having issues with the sound system ever since. When I turn on the rear seat audio (RSA) controller, the speakers produce a buzzing and humming noise, and the sound is very faint. When I turn off the RSA, the buzzing stops. When the engine speed increases, the noise does not change but remains constant.

I’m trying to troubleshoot without buying a new RSA unit because the shipping costs to Germany are very high. I’d like to know which pins on the connector need to be bridged to bypass the RSA and see if the buzzing comes from the RSA or my CANBUS adapter (PAC RP5-GM31).

Has anyone dealt with a similar issue or can provide a pinout for the RSA connector? Any advice would be greatly appreciated!

Thank you in advance!

I do not know the pinout but you can probably find it in the GM upfitter guide (full size electrical)

Light Duty Prior To 2013 - GM Upfitter

www.gmupfitter.com

 

[Joseph Garcia]

Welcome to the Forum from USA.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

 

[Manuux96]

I do not know the pinout but you can probably find it in the GM upfitter guide (full size electrical)

Light Duty Prior To 2013 - GM Upfitter

www.gmupfitter.com

Thank you!
The green plug of the radio control must be bridged from top to bottom to bypass this. Unfortunately, that did not solve the problem and the humming also occurs with the radio unit bridged. So my guess is that the Bose amplifier has a bad ground connection, the amplifier is defective or a speaker is short-circuited.

 

[Manuux96]

Welcome to the Forum from USA.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

Thank you for the good reception here!

I have attached some pictures. There are a few things that need to be modified in order to be allowed to drive an american car in Germany.

 

[Doubeleive]

Thank you!
The green plug of the radio control must be bridged from top to bottom to bypass this. Unfortunately, that did not solve the problem and the humming also occurs with the radio unit bridged. So my guess is that the Bose amplifier has a bad ground connection, the amplifier is defective or a speaker is short-circuited.

I could be wrong but I think some have reported that the rear control could be the issue (making noise), you might try searching around a bit to confirm or deny

 

[Manuux96]

I could be wrong but I think some have reported that the rear control could be the issue (making noise), you might try searching around a bit to confirm or deny

I disconnected the rear control and bridged the cables of the plugs, so I bypass the rear control

 

[Doubeleive]

I disconnected the rear control and bridged the cables of the plugs, so I bypass the rear control

did that solve the problem? if not if you have a capable scanner you can test the amp channels, this will create a tone on each channel, not sure if the noise would be present or not but if it is then that may confirm if it is the amp or not.
maybe also you could try to switch the input signal for that channel and see if the problem follows the input, if so that would make the problem the head unit.

 

[Manuux96]

did that solve the problem? if not if you have a capable scanner you can test the amp channels, this will create a tone on each channel, not sure if the noise would be present or not but if it is then that may confirm if it is the amp or not.
maybe also you could try to switch the input signal for that channel and see if the problem follows the input, if so that would make the problem the head unit.

No, the noise also comes when the plug is bridged. It doesn't matter which channel is set on the radio. The front speakers work perfectly, but the sound from the rear is very quiet and the loud noise comes from all rear speakers.

what kind of tester do I need? Unfortunately, there is no information about this in Germany

 

[Doubeleive]

No, the noise also comes when the plug is bridged. It doesn't matter which channel is set on the radio. The front speakers work perfectly, but the sound from the rear is very quiet and the loud noise comes from all rear speakers.

what kind of tester do I need? Unfortunately, there is no information about this in Germany

a tech2 or tech2win (pc software/obd interface) would do it for sure, not sure if other scanners would do it or not

 

[mikez71]

I wonder if the aftermarket radio is powering the amp or driving speakers directly? Line output or speaker output to amp may affect noise level too?

What I have found, when hitting the RSA button, the rear radio outputs go full volume. Amp probably mutes rear speakers and redirect output to headphones jack..?

 

[Manuux96]

a tech2 or tech2win (pc software/obd interface) would do it for sure, not sure if other scanners would do it or not

all right, thank you for your information. I'm trying to get a scanner like that.

I wonder if the aftermarket radio is powering the amp or driving speakers directly? Line output or speaker output to amp may affect noise level too?

What I have found, when hitting the RSA button, the rear radio outputs go full volume. Amp probably mutes rear speakers and redirect output to headphones jack..?

So if I unplug the cable from the Bose amplifier, the front speakers go silent. So my headunit has to turn on the amplifier. As soon as I turn on the RSA and plug in headphones there is a humming noise in the headphones and no sound comes out when something is playing.

 

[Manuux96]

Could this all be related to my Canbus adapter? I don't know if I have Onstar in this vehicle or not. To be honest, I still don't fully understand what Onstar is, we don't have this service. I have the PAC rp5-gm31 in conjunction with an Alpine ILX 705 radio. Maybe the Bose amplifier doesn't like the Canbus adapter and that's why there is no music coming out of the rear speakers, just strange noises.

 

[mikez71]

Do the rear speakers work normally?

 

[Manuux96]

Do the rear speakers work normally?

No, Just noise

 

[mikez71]

Is it possible your aftermarket headunit does not support rear seat audio?
I believe it lets the driver listen to one audio source and the rear seat audio (headphones) uses a second source.

If you don't have sound out of your rear speakers normally, then maybe your amp is bad or somehow the wiring is wrong?

 

[Manuux96]

Is it possible your aftermarket headunit does not support rear seat audio?
I believe it lets the driver listen to one audio source and the rear seat audio (headphones) uses a second source.
View attachment 432920

If you don't have sound out of your rear speakers normally, then maybe your amp is bad or somehow the wiring is wrong?
View attachment 432918
View attachment 432919

So, as I said, I can hear the radio sound very quietly from the rear speakers when I put my ear to it, but the noise is much louder. My radio definitely has outputs for the rear speakers. I ordered a new amplifier today and will replace it. If that wasn't the problem, I'll check the cables for all the rear speakers maybe one of the speakers has a short circuit.

 

[Manuux96]

Small update: I installed a new amplifier and the noise is gone but there is actually no sound at all coming out of the back. I bridged the speaker cables of the rear speakers and connected them directly to the vehicle wiring harness without success. Unfortunately the original rear monitor and DVD player were replaced by the previous owner and so I can no longer change the source on the rear controller but it is set to radio which should be fine. I'm absolutely at a loss as to what else I should try. Maybe it really is the PAC adaptertely without success.

 

[petethepug]

Try this ….