2003 BMW 745Li Seat Heater Switch Replacement Cost

Heated seats are an option in some cars, trucks, and SUVs that allow the front seats to be warmed in cool climates. Occupants can enable one or more heating elements inside the seat cushions by way of the seat heater switch. This switch may be mounted in the center console of the vehicle, in the front door trim panels, or in the climate control center located in the dashboard.

When the seat heater switch is turned on, it sends a low voltage signal to actuate a relay that powers the seat heater element. The seat heater provides resistance against the electrical current and produces heat - similar to the way a toaster works. The wires of the seat heater are laced back and forth across the seat cushions underneath the seat cover in order to distribute the heat evenly across the surface of the seat. A sensor is used to measure and regulate the temperature of the seat heater. A control module may be employed to aid in temperature control. And some vehicles have a built-in timer to shut the heater off. The seat heater switch may enable one or more heat settings.

While the most common problem with heated seats is an inoperative seat heater element (often due to a break in the thin wires that make up the heating element under the seat cover), a bad seat heater switch can also be at fault. Other complaints include a switch that works intermittently, comes on by itself, or turns on momentarily before switching itself off. Some drivers complain that the heater becomes too hot. In some cases, a malfunction in the seat heater can cause the heating element temperature to rise too high, causing burns to the occupant.

A seat heater that does not work properly is not usually a cause for concern. In most cases it simply will not work. If a short circuit is the cause, though, damage to sensitive components in the electrical system could result. A seat heater that is malfunctioning and does not regulate the temperature properly can get too hot and cause burns to the occupant. This condition should be checked and repaired as soon as possible.

Seat heater components installed at the factory are expected to last the lifetime of the vehicle. However, excessive wear on the seats can decrease the useful life of the delicate seat heater elements under the seat covers and switches can wear out over time.

Understanding that a faulty seat heater element is the most common seat heater problem (and the most difficult to repair), a technician will begin diagnosis with the simplest possible explanation. A blown fuse can be both the result and cause of a seat heater problem. If the fuse is intact, the technician will check the circuit for proper voltage at the switch, the heating element, and the control unit. A faulty relay is a potential problem that a technician might look for, as is a problem with a computer control module on some vehicles. A diagnostic scan may reveal trouble codes enacted by the seat heater and point toward a possible problem.

Once a technician determines that indeed the seat heater switch is the problem and not the heater element, relay, or control module, the next step is to replace the faulty switch. On most vehicles the seat heater switch is located in the center console or in the door trim panels. In some cases, the switch is integrated into the climate control panel in the dashboard. In the latter case, replacement may be a difficult and expensive operation. in the cases of the simpler and more accessible switches in the console or door panels, a technician will remove the necessary trim to access the switch retainers, and, with the ignition off (and possibly the battery disconnected) disconnect the wiring harness plug and remove the switch. The new switch is put in place, wiring reattached, and trim components installed. The technician will verify that the repair is complete by testing the seat heater(s).

RepairPal recommends that drivers pay particular attention to whether or not the seat heaters are switched "on." It may be difficult to gauge how hot the seats are getting until they are too hot. The auto industry is beginning to take notice of the concern and may one day make the control center for the seat heater more visible to occupants, but for now it is important to pay attention. See a repair professional if the seat heater is not working or if it gets too hot.

It should be noted that, when using a seat heater, it is important to pay attention to how hot the seat is getting. Some drivers complain that, even under normal circumstances, the seats get too hot. Some complain of injury and burns. Occupants with certain health concerns that lead to sensory deprivation or skin conditions, as well as young children, may be especially susceptible to injury associated with seat heaters.

In many cases, seat heater switch replacement can be done by someone with intermediate DIY experience. However, the most difficult aspect of the repair is not the process of installing a new switch, but rather in accurately diagnosing the problem in the first place to avoid replacement of unnecessary parts due to improper diagnosis. A professional technician will have access to the proper equipment and vehicle-specific data necessary for an accurate diagnosis and repair.