2020 BMW 840i Power Seat Control Module Replacement Cost

Power seats in a car, truck, or SUV allow for the driver or passenger to custom tailor the shape or position of the seats for maximum comfort at the push of a button. The power seats are adjusted with a number of small motors inside the seat. The operator presses a control switch that signals the power seat control module to trigger a relay that turns on the motor. Power seats may incorporate forward, backward, up, down, tilt, lumbar support, and even headrest adjustments. In many cases, settings for multiple occupants can be memorized by the seat control module (or by the Body Control Module). Some vehicles with a heated seat option may locate the heater switch with the power seat switches as well. With some vehicles, the control module is an electronic control unit (often mounted under the seat) that is separate from the switch assembly. With other vehicles, the control module is integrated into the switch assembly.

The seat control module receives electrical current from one or more switches that, when actuated, send signals to relays that control the power seat motors. Adjustments are coordinated - in some cases memorized - by the seat control module. These operations, along with dozens of other functions of the vehicle body (power mirrors, locks, windows, airbags, alarm, et. al.) may also be overseen by the Body Control Module.

Symptoms of a malfunctioning power seat control module might include the seat not moving in one or more directions when the switches are actuated, or the seat not moving at all. On vehicles equipped with seat heaters with controls mounted with the power seat controls, inoperative seat heaters may be a symptom of a faulty control module. Also, in some cases, seat setting memory loss may result from a bad seat control module. Occasionally, a dead battery or a blown fuse can be a symptom of a bad control module as well.