I put 26in rims on my 2008 sierra 1500 and the service tire monitor system came on. how do i turn this off?

You have to change the stems out of your old tires to your new ones if it isn't already done. the old stems have the pressure monitors on them that tie into your trucks TPMS(tire pressure monitoring system). You can look in your manuel and find out the steps to reseting once it is done. I recommend taking it to discount tire after stems are in new wheels.....they will reset everything for free. If you take your old tires and let them do everything it will cost bout $400. I just put 26in. rims on my 08 sierra also and have same light. No big deal you just wont ever know if your pressures are low in your tires.....some people will change your stems out for a cheaper fee. I suggest that and then take it to discount and let them reset everything. Cheapest way... You have to change the stems out of your old tires to your new ones if it isn't already done. the old stems have the pressure monitors on them that tie into your trucks TPMS(tire pressure monitoring system). You can look in your manuel and find out the steps to reseting once it is done. I recommend taking it to discount tire after stems are in new wheels.....they will reset everything for free. If you take your old tires and let them do everything it will cost bout $400. I just put 26in. rims on my 08 sierra also and have same light. No big deal you just wont ever know if your pressures are low in your tires.....some people will change your stems out for a cheaper fee. I suggest that and then take it to discount and let them reset everything. Cheapest way...