it COULD be a guy looking for a faster response
Good God, are there really people who think that way these days?
I agree with Basscatt though. If you are uncomfortable doing it yourself. Take it to a professional who has REPUTABLE experience with these cars. The stereo unit on them is known for it's trickiness.
Alternatively, if you are the do-it-yourself type, it really cannot be THAT difficult. No matter what anyone says. It has been done before and speaking realistically, no matter what anyone will try to tell you, car electronics are not that complicated (Really I mean, I remote started a car from 3,000 miles away this one time using only a broken prepaid phone and the relays, wire and zipties that happened to be in my backpack at the time)
However, if you are going to do it yourself, I would suggest you arm yourself with the following.
Proper installation instructions for the head unit as apply to your car (there will usually be different instructions for different applications, as not all cars are the same)
A Factory Service Manual for your EXACT car. Same year, same model.
Lastly, I would ask for any additional assistance from the folks in this section of the Forum, as they should be most experienced with the design of this car.
http://www.cadillacforums.com/forums/cadillac-deville-1985-2005-including-1985/
A quick search gave me the first result, which seems relevant to your conundrum. You can find it here:
http://www.cadillacforums.com/forum...stems/153651-1996-deville-stereo-install.html