Everywhere I see on the net and on my car is different. I have a 99 deville non bose radio with theft lock and 12 disc changer in the trunk. I'm seeing where one would have to wire the entire radio or a buy a 100 dollar interface to keep the car from acting stupid after a HU changeout. I unplugged my stock radio and drove the car for a few days without a radio in there and the only thing I noticed different is that my door chimes were gone, about it, no crazy locking doors or car not wanting to start nor any messages on my dash readout. Now what would be insanely useful is a accurate wiring diagram for this base system. My stereo will be here in a couple days and I seriously thought about breaking the radio down to the mobo and enclose it with something to keep it from shorting out and drop it being the aftermarket. From what I can see is the board is not that big in the delco unit and I believe once broken down and plugged in the car will see the original radio is there and operate as nornal, such as door chimes and R.A.P. and drivers memory buttons. The only wires I think that could be cut from the radio are the speakers wires. 12v switched can be tapped into and one would have to run a 12v constant independently anyways. Soon as I find a small socket I'm going to finish breaking the stock delco down to the board and plug it back in and wire in my new unit and see how it goes. If it does work I would like to know the SWC wires for the new unit to test if that can work also. I'm really not into buying a bunch of other stuff just to do something that I should be able to do anyway. I'm not doing the relocation thing neither, which is the reason I'm here. I will post back what happens when new unit comes in. If this works it save alot of money, the main thing to worry about is how to cover and hide the mobo with the heat sink still on it.