Hi Folks,
A few months ago I installed an X920BT in my 2008 Hummer H3 using the GMOS-01 adapter to retain OnStar and chimes.
Everything about the install works great except for the day / night mode on the X920BT. I checked and double checked my connections according to the X920BT and GMOS-01 installation guides and they are correct; however, night mode still does not work.
I have Googled around and searched on this forum and have read that the illumination wire / circuit on the GMOS devices do not work and that the solution is to hard wire in to the illumination wire of your vehicl