As far as milage mine just turned over 17,000 miles. '21 3500. Can't remember exact engine hrs but somewhere in the 700 range. 500ish driving/200ish idle time. Mine has been running the grid heat cycle most mornings for the last month or so and early last spring a lot.I think it is a manufacturing defect rather than a design defect but time will tell. I have no idea what kind of QA tests or checks they do to the relay before it is shipped to RAM. Obviously a run of relays got into the field that should have been caught in house. If it is a design flaw like the CP4 pumps then a replacement design should come in the future and we can all upgrade to that. Hopefully if it comes to that it will be plug and play. Who has the most miles on the original relay? One guy at work has 14,000 already on his 21 3500 DRW and so far no issues. He is scheduled to go in for the recall test soon. Has anyone on the forum had a fire?