The other day on my 2005 Escalade Ext my speedometer began to act erratically. I would be going around 40 and it would read 80mph. When I shut off my vehicle, the needle stayed at 20. Next day it read even faster as I was driving. Today it stopped at 60 mph when vehicle was turned off. Ironically, my Escalade is in for inspection today. The dealer said that this is a "common problem" and that the ENTIRE instrument gauge panel will need replaced. Every other gauge works perfectly fine. This all began with all of this cold weather but I am sure that is coincidental. My question is this?? Do I need the entire cluster with all gauges replaced? I have learned unfortunately that many times the dealer is not correct and that is why I am seeking advice from my fellow Caddy owners here. I guess I thought there was a way to "recalibrate' the speedometer or some other way to "fix it". The dealer said the cluster would cost around $300.00 and God knows what the labor would be. Anyone able to give me an expert opinion? As always, thank you everyone for your time and advice. This forum is a great place to seek help.