I have a '09 model with heated leather seats. The front passenger seat cushion (bottom) didn't seem to heat like the driver's seat. Only the back of the front passenger seat seemed to warm well. Took it in for service, thinking there might be a wiring problem. Turns out, there's a GM service bulletin #09-08-50-013 (Aug 2009), "Information on Front Passenger Heated Seat Insufficient Heat" that explains this "problem". It advises dealers to not replace heater elements because it's normal, and due to a "sensor mat" and different wiring grid in the front passenger seat. That causes it to not heat as well as the driver's side. Anyone experiencing this should check with their authorized dealer and confirm that they don't need to have the seat disassembled and repaired.