I thought one of my sensors was bad on my 2008 Silverado because my TPMS light has been on for about a year. FF to yesterday when Discount tires wouldnt balance or install the set of wheels and tires that I purchased off of craigslists w/o removing and using the old sensors from my truck on the new set of wheels and tires. I was going to get them to replace the bad sensor ($60 each) so that damn light would go off but all of the sensors were working per their scan tool. I'm glad I didnt have to shell out $60 per sensor but Im totally confused as to why the light is still on. I'll check the spare when I get home but I cant imagine it having a sensor. any other ideas?