Pontiac Repair: keyless entry receiver, rear speaker, remote start

Question
I took my 05 grand prix to the dealer to reprogram the key fob, but was told that my receiver was bad.  I was looking to replace it myself but do not know where to locate it.  It is a 2005 base model with original keyless entry and no remote start.  Could you please help?
Matt

Answer
Hi Matt:

That is located on the rear package shelf behind the rear seat. It's on the right side of the car by the rear speaker. You need to take that shelf off and it's under that. It is a small black plastic box that is about 3"x4" square with one connector and maybe 3 or 4 wires in the connector. Hope that helps.