An occupant detection system including a seat assembly comprising a seat cushion having a seating surface, a heating element adjacent the seating surface, said heating element formed of electrically conductive material, a heating circuit electrically coupled to the heating element, said heating circuit configured to supply an electrical current to the heating element effective to generate heat by the heating element, an occupant detection circuit electrically coupled to the heating element, said occupant detection circuit configured to detect an occupant presence near the heating element, and an isolation circuit interposed between the heating circuit and the heating element, said isolation circuit configured to prevent the heating circuit from influencing the occupant detection circuit, said isolation circuit comprising a common mode choke. The common mode choke is arranged so current or charge from an excitation signal for detecting an occupant that is received by the heating circuit is replaced so the excitation signal can used to accurately detect an occupant.