How do the tire pressure sensors work on a nissan titan. Can I change to aftermarket rims easily?

I want to upgrade to an aftermarket rim for my nissan titan. I am confused how this will affect my tire pressure sensors. My dealer said not an issue if I stay with a similar rim but offered no other details. Is the sensor located in or on the factory rim, if so, can it be transfered easily to a new rim? I do not want a constant idiot light showing on my dash.|||Most sensors are part of the valve stem. If you can transfer them to the new wheels you should be ok.