2001 Cadillac STS passenger heated seat

More than likely you have an element that has opened, or in other words high resistance. Often times it is the cushion, and typical layout of an STS has 5 elements. Two cushion thigh, and one cushion, accompanied with a seat back element. If you can determine, out of all the connectors under the seat, which are for the elements, then you can measure the resistance. The cushion element is a four wire connector(red/black/and two gray), and the seat back is a two wire(red and black I think). The thigh elements are connected to thee seat cushion element harness, under the rear cover flap. The elements are not too expensive, if you replace what you need. If you are comfortable with seat upholstery, then you can attempt it. Some are fastened with hog rings, and some had velcro, not sure what you have. The foam has to be slit, and the new elements slid in between the old element and the leather. It is a bit of a challenge, and the seat won't look the same after you are through.