Does Anyone know if there is a way to get the head unit to communicate with the Invision system? Manuals say if they were "factory installed" the head unit will recognize and be able to control the rear DVD systems. Problem is, I don't think any were ever installed at the factory. Mine apparently weren't.
I realise this is very late, but when ever I'm looking up this problem, this thread is always at the top of my search list.
I've been scouring the net for about a month on this one since upgrading to a 2011 EL, has Invision in the rear, and I'm just about to stick our old Kenwood video head unit in from the old 06 Expy.
basically you can look in a lot of forums to see the discussions on invision systems from Hummer, to Cadillac, to Nissan, etc.
Invision say you need to upgrade to the Revolution GIII control box, which is available form your dealer, (most of which will have no clue what your asking for) I've found them here:
NEW Genuine Invision GM Ford Toyota Nissan Honda DVD Headrest FUNBOX Control Box | eBay
seems to be the only way other than some very careful and blind splicing (it seems to be impossible to get a copy of either the wiring diagrams or the pin definitions), this control box will give output and aux input feeds to go to your head unit.
I'm ordering one, will let you know how i get on.