Hi I recently installed a 930BT in my 2005 Chevy SSR 6 speed. I utilized a GMOS-04 harness to do so since my truck has the Bose premium sound system.

I performed the video bypass mod successfully as well.

I however am having an issue with the voice navigation volume, it is ridiculously low even though I have it set to max volume in the radio settings. I swear when I hear the voice it sounds like it is coming from the center of the dash where the GMOS-04 is located and not through the regular speakers.

In addition to the very low volume, the current music source is not lowered/muted when the navigation voice is activated making it more impossible to hear it.

Obviously it isn't supposed to be this way but I am looking for some direction in regards to troubleshooting the problem.

I assume moving the MUTE wire has nothing to do with the audio not stopping while voice is being played?

I also noticed when I have the volume turned up to higher levels the sound appears to start hopping between the left and right speakers. I am guessing this may have to do with the audio output adjustment on the GMOS-04 although even though set to a max volume (40), the system doesn't sound as loud as it should be.

Any ideas would be greatly appreciated. I will be ripping the dash apart soon to see if I can get it all figured out.

I see in the GMOS-04 install manual it speaks of attaching the brown wire to the MUTE wire off the radio, since the wire is moved and grounded with the bypass, I wonder if this is the source of my issue?

wild guess: do you have the polarity (phase) inverted on one or more of your speaker wires?

Nav volume and attenuation are in the settings.

Just an update, the issue was resolved by ripping the dash apart again and tweaking the output potentiometer on the GMOS-04. I now have great volume!