So probably most of you guys with more than 200,000 miles on your rig probably notice the check EGR light. I found something out, when I was changing my odometer from my old cluster to my sport cluster (so It would say 208,xxx miles instead of 225,xxx miles that the sport odo said) I noticed the wires from the EGR switch run to the odometer, and there is another switch inside of the odometer that is turned on by a gear with a cam on it. So the check EGR light is mileage dependent, it doesn't mean anything is wrong with with your truck. I thought that was pretty neat and wanted to share it.