What's the 2004 Cadillac DeVille factory amp location?

If You (or a previous owner) has not upgraded the factory Audio equipment in the 2004Cadillac DeVille, You should be able to find the amplifier in the same location across all trim levels. It will be located behind the rear seat, in the rear electronics bay. In order to access it, You'll need to remove the carpeted trunk liner, and drop the plastic panel that's located behind the rear seat bulkhead. You may be able to see them, but unfortunately there's not much of a way to do anything with it unless You remove the seat-back. If You're looking to upgrade, it's more commonly advised to just bypass the existing amplifier; aftermarket equipment will sit in Your trunk nicely with a quality subwoofer and amplifier box.