2001 Durango SLT 4.7 4 x4 Auto. Leather seats. Drivers seat heater not functioning. The button on the console for the drivers side just blinks. Was told there are two seperate heating elements in the seat 55056249AE and 5093306AA. If one goes out, neither will work. Does this sound correct? How would I know which one needs replaced? Is there any other common causes besides the element?