Common Power Seat Problems
Once you have an automobile with power seats, it’s hard to go back to the regular ones. The ability to make small adjustments to achieve the most comfortable position is always desirable, but on long cross country trips can become essential. Just being able to slide up and back can seem barbaric after experiencing the total luxury of a twelve way heated power seat with inflatable bladders that allow for total control of lumbar and side support. The downside is this luxurious accessory provides another complex area of possible repairs. This article will explore unique symptoms of different issues and some common power seat problems.
Types of Power Seats
Power seats are available in a few different configurations categorized by the number of adjustments they are capable of making in different directions. Once the most common would have been a simple four-way adjustable, this was replaced by six and twelve way adjustable. Now some luxury brands have pushed the limits to include seats that have 22-way power ventilated comfort seats with AC, heat and massage, plus four-way power lumbar adjustment, with multiple driver memory retention.
Four and Six Way Power Seats
When diagnosing power seat problems it’s often good mentally to return to the basic operation of a four-way power seat. These seats move up and down to raise and lower passengers and front to back to adjust leg room. Generally speaking most car manufacturers use two motors to accomplish these movements. A lift motor raises and lowers the seat while a position motor moves it forward or backwards to allow for drivers of different heights.
When car makers upgrade to a six way power seat, it actually only requires the addition of one more motor. The position motor is still responsible for moving the seat forward and back, but now there will be a front lift motor and a rear lift motor that operate independently from each other. This allows for the bottom cushion of the seat to not only be raised and lowered but also tilted so the front is higher than the rear or the inverse.
Diagnosing Power Seat Problems
Analyzing symptoms can go a long way in pointing you in the right direction when problems are experienced. Seats that are completely inoperative and don’t move in any direction when switches are activated can indicate a power supply problem, such as a malfunctioning circuit breaker, relay, or fuse. When these individual devices check okay, it’s time to verify that power is actually making it to the master switch.
If a good power supply and ground is located at the switch and no power is coming out, this could indicate a failed master switch. When certain functions are operating, yet others do not, it’s important to consider what these features have in common and do not. As an example if all of the functions on a power seat work except the ability to raise the back of the bottom seat cushion, Testing between the function switch and the motor that lifts the cushion should be concentrated on. Individual switches can fail just as easily as wiring connections and motor functions.
Power Seat Doesn’t Move Forward or Back
Although these power accessories can be extremely complicated with all of their motors, functions and switches the base of the seat where it attaches to the floor often resemble standard automotive seat tracks found on any modern automobile. These are two heavy steel tracks that slide inside of each other. The design allows for movement while securely holding the seat to the structure of the automobile.
One of the more common problems that mechanics will find is unwanted debris or contamination of the seat tracks. Spare change or things dropped by the driver and passengers can work their way down into the seat track and jam the assembly. In the same regards, soda, coffee and other sticky syrup based liquids can be spilled into the seat tracks and then dry into a surprisingly strong movement inhibitor. The position motor responsible for moving the seat forward and backwards in the track has an overheat protection either built into the motor or via a circuit breaker mounted in the automobiles electrical panel.
When the seat binds the motor will try to move it for a few seconds and then automatically turn off to protect itself. If you are not sure if the motor is entering this protective mode or engaging at all, professional mechanics employ a little trick. With the door open and the dome light illuminated activate one of the seat movements. When the motor engages the dome light will dim slightly. When the motor enters it’s overheat protection mode the dome light will come back on full strength.
Although power seats have moved from simple four-way to extremely complicated twenty-two way adjustable contraptions, diagnosis and repair of the two vastly different systems can still be approached in a symptom-based logical manner. By analyzing what is working and what is not working can go a long way towards pushing you down the tree chart and reaching the box that indicates the failure quicker.