03 Denali Speedometer

I have an 03 Denali and the speedometer is way out of wack.Sometimes it would show different speeds even though i know im not going those speeds.Seems like its stuck or something.I asked a friend and he said that there is a sensor on a small circuit board and it must of broke or something he also said thats a known issue with GM cars.Does anyone know anything?Thanks in advance.

I have a 2003 yukon that had the same problem. The whole instrument cluster had to be replaced at a cost of $450.00. It has worked good ever since.
Greg

If it's an '03, I assume you might still be under warranty depending on mileage. If not you might want to look on ebay for a used one with similar mileage or even get the Escalade one with the chrono-style gauges. Do you have oversized wheels/tires that don't match the OE rolling diameter? If so, you might want to get your new speedo cal'd to match the new rolling diameter size of your wheel/tire combo.

I have 24" rims (295/35/24) and where would i get it calibrated at?

Dealer will do it. I've heard of it costing ~$200. I hope you upgraded to a big brake kit. 24" rims have a lot of rotational mass that will just destroy your stock rotors and pads.