[RustyBlazerDude]

OK.
Not too many responses, but here is a picture of the unit with the harness. Again, this simply plugs in to where the old analog onstar viu was and enables you to use the buttons on the mirror, along with the onstar high quality microphone to allow you to connect directly to your bluetooth cell phone.

I think this will work with most cadillacs of this vintage (circa 2000) and should also work with any GM having analog onstar unit that utilizes class 2 data bus for communications. The harness may be slightly different for other GM vehicles.