Mmmmm?? Did they not mention anything about a recall for this particular problem? Click here to see the service bulletin.
Oh well. I was hoping it was. Either way this recall bulletin shows how to remove and replace the multiplex unit and should walk you through with no problems. If you want to save some money on the part, you might try here www.evansautomotive.net I have bought these used from here before for $25.
If you need anything else, please let me know.