So as some of you here know I just upgraded from the JVC KW-NT1 headunit to the KW-NT3HDT a months or so ago before I went away on holidays.

The headunit is great! No regrets, it matches the interior much more than the old HU. One thing that caught my attention when I was installing the new HU is when I removed the old one there was a brown "Mute" from both the HU and the GMOS-09 harness. So every time I used to push the OnStar button I used to see the word "Mute" on my screen and then OnStar kicks in and work like a charm


The new HU doesn’t have a "Mute" wire into it, so I left the brown wire from the GMOS-09 loose. Now every time I press the OnStar button the HU completely shuts off. As soon as the OnStar conversation is done, the HU turns back on.

Any ideas what’* going on?

only thing i can think of is that wire shorting out to some thing?

i have no idea, my brother is using a different GMOS for his grand prix and same thing happend with two HU, both shut off because they dont have a mute wire, which i find very stupid

The product manuaI says "THE BROWN LOOP ON THE 16 PIN HARNESS MUST BE CUT, THEN TAPED UP. PLEASE REFER TO THE ONSTAR LEVEL ADJUSTMENT SECTION FOR FURTHER
DETAILS ABOUT THE BROWN WIRE." manual located here http://www.metraonline.com/files/pro...NSTGMOS-09.pdf I think you have a short if like you say it is just hanging loose and not taped up.

I see your factory system would be similar to mine since you have Onstar. Can you see if you can answer the questions in my thread about replacing the head unit using the GMOS-09? https://www.gmforum.com/audio-aftermarket-electronics-101/scrapping-monsoon-system-ma-audio-system-298443/

i already have the HU installed and this would be my second on, theres no short
and yes you are right the brown loop wire must be cut, but im talking about a different brown wire, no loop, its the mute wire that puts the HU in mute when the phone is activated, im not complaining about my GMOS-09. im complaining about the HU