I have a 2003 Cadillac Deville that is overheating. It seems like the only time it overheats is if it is idling on a hill, uphill. It doesnt when im stopped at a light or running or driving. I recently replaced the thermostat and it didnt fix the problem. I had the coolant flushed a few weeks ago so it has good coolant and is full. The fans do work but i have had alot of people say that maybe a relay or the temp sensor might be bad???? Anyone have any suggestions as to what to do next?? Also no leaks at al as far as i can tell.