09 Silverado: HU, XM, and camera working, but no onstar, chimes. For those familiar with the GMOS non-amplified install, when I attach the yellow wire from the GMOS 12 slot connector to constant 12v source per instructions, the HU turns on. This can't be correct - or the HU would be on all the time, until the battery dies of course. Bad GMOS or ???