Heated car seats use a heating coil embedded below the seat cover. Electricity travels through the coil and is emanated as heat, because the coil acts a resistor. This form of resistance creates enough friction to produce a safe form of heat that can be felt through the seat. The heating coil is usually controlled by a relay switch that mechanically triggers the coil to receive electrical current. Check the relay switch before replacing the heating coil to help confirm that replacement of the coil is necessary.
Unbolt the seat using a ratchet and socket, and unplug all electrical wiring connected to the seat by hand. Depending on the make and model of the vehicle, there should be one electrical connection for the coil and another for the electric seat adjustment lever. Lift the seat out of the car. Detach the circular Hog rings connecting the seat cover to the seat using pliers. See your vehicle owner's manual for the exact method to remove the seat cover.
Grab the coil with pliers, then pull it out of its socket. Install the new coil by plugging it into its socket by hand.
Reinstall the seat cover using pliers to secure the Hog rings. Place the seat back into the vehicle, then plug in the electric seat adjustment lever and heating coil electrical connectors by hand.
Reinstall the bolts at the base of the seat, using a ratchet and socket.
