Head unit wire harness

Hey all - anyone know what color the POWER wire harness is for the back of the OEM head unit on a 2004 Blazer 4x4? My HU was unplugged by the dealer several months ago (long story), and I've now fixed it and want to plug it back in. However, I can only find the speaker channel harness (gray taped wires with white/blue plastic clips) and the antenna cable. I'm not sure where the tech shoved the power harness, and/or what to look for under/within the dashboard. I can't see anything dangling (the other two plug-ins were *right* there behind the HU) so it must be shoved way back in a crevice somewhere. TIA for any assistance -