Audio Systems: aftermarket radio install in2004 GM, 4wd vehicles, gm dealership

Question
I heard from a local installer that everything (just about) is ran through the radio on 2004 Gm sierra 4 dr. I will need a $80 part to allow me to install a aftermarket cd changer in my truck. Or I could risk oil pump problems or air bag or anything could happen, problems if I dont install this module. Is this so?

Answer
Wayne,
I don't have any info on the 2004 GM Sierra 4wd vehicles. I have a contact at the local GM dealership and I will check out the problem that you mentioned. I will let you know something in a couple of days.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net