Heated Seat Module - Operation

OPERATION

The Heated Seat Module (HSM) controls the heated seat system. The HSM responds to heated seat switch messages and ignition switch status inputs by controlling the 12-volt output to the seat heating elements through integral solid-state relays.

When either of the front heated seat switches are pressed, a request signal to supply power to the heating elements for the selected seat is sent to the HSM over a hard-wired circuit. The HSM energizes the integral solid-state relays that supply battery current to the heating elements. When high-level heating is initially selected, the HSM provides a boosted heat level during the first four minutes of operation, then the heat output level drops to normal high setting. When high setting is first selected, the system will automatically switch to low-level temperature after approximately thirty minutes of continuous operation. At that time, the number of illuminated indicator lamps in the heated seat switch change from two to one, indicating the temperature level change. Operation on low-level turns off automatically after approximately thirty minutes.

The heated seat system operates on battery current received through a fused ignition Run circuit, so that the system will only operate when the ignition switch is in the On position. The heated seat system will turn off automatically whenever the ignition switch is turned to any position except On. With a heated seat on, if the ignition switch is turned to any position except On, the heated seat system will turn off and remain off, until the engine is restarted and a seat heated seat switch is pressed again.

The HSM is diagnosed using a scan tool and will automatically turn off the heating elements if it detects an open or low short in a heating element circuit.