as for the rotation someone said it earlier... it'll only effect the reading in the sense of what tires it says is low. what probably happened depending on where you went? some of the techs aren't familiar or trained to change tires or wheels with sensors its possible one or more of them were broke in the process. if this is the case take it back to the tire shop immediately and have them pay for the damaged sensors! THEY AREN'T CHEAP... about $50+ a sensor. as for the temp difference it was also stated earlier temps only going to drop the pressure 5 degrees or so and it takes a 25% drop in pressure to set of the light. i recommend havin a tire taken off by the CHRYSLER dealer and see what they find out!