Lexus IS, RC & GS Seat Motors (2014-2025): A Guide to Movement, Lumbar & Ventilation Motors

Understanding the 'Seat Motors' in Your 2014-2025 Lexus

When a power seat function fails in a 2016-2025 Lexus IS300, 2014-2025 Lexus IS350, 2021-2025 Lexus IS500, or other related models like the RC and GS F, owners often assume a single 'seat motor' is the culprit. However, a modern Lexus power seat is a complex assembly containing multiple, distinct motors for different functions. Purchasing the wrong part is a common and costly mistake. This guide breaks down the different motors, their unique part numbers, and how to identify the correct one for your repair.

Variant Differences: The Most Common Buyer Traps

Before buying any used seat motor, you must verify your vehicle's options. These are the most significant differences that determine which part you need.

1. Memory vs. Non-Memory Seats

Vehicles equipped with the memory seat package have motors that are physically different from those in non-memory seats.

• Memory Seat Motors: These motors have a small sensor called a Hall effect encoder attached to them. This sensor counts the motor's rotations, allowing the seat's control module (ECU) to know the exact position of the seat at all times. This is how it can save and recall positions for different drivers. The wiring connector for a memory motor will have extra pins for this sensor.
• Non-Memory Seat Motors: These are simpler, typically with just a two-wire connector for power and ground. They do not have position sensors.

You cannot use a non-memory motor in a memory-equipped seat, as the system will not be able to determine its position. While you might be able to wire a memory motor into a non-memory seat, it's not recommended and may not fit or function correctly. The easiest way to verify is to check your driver's door panel for the 'SET', '1', and '2' memory buttons.

2. Ventilated (Climate-Controlled) vs. Standard Seats

If your seat has heating and cooling functions, it contains two additional blower fan motors. These are entirely separate from the motors that adjust the seat's position.

• Part Numbers 85860-33040 & 85867-53030: These are the blower motors for the driver's side (Left Hand) seat cushion and seat back, respectively.
• Part Numbers 85860-33020 & 85867-53020: These are the blower motors for the passenger's side (Right Hand) seat cushion and seat back, respectively.

Failure of one of these motors will result in a lack of airflow for the heating or cooling function, but will not affect the seat's ability to move.

3. Lumbar Support Motor

The lumbar support mechanism is a self-contained assembly with its own motor.

• Part Number 72750-76010: This is the OEM part number for the lumbar adjuster assembly. Failure of this part means you won't be able to adjust the lumbar support, but all other seat movements will work normally.

Symptoms of a Failing Seat Motor

Symptoms will vary depending on which motor has failed.

• Seat Won't Move in One or All Directions: If a specific function like sliding forward/backward or reclining fails, but others work, the motor for that specific function is the primary suspect. If no functions work, the problem is more likely a fuse, the main power connection, or the switch itself.
• Slow or Intermittent Movement: A motor that struggles to move the seat, moves very slowly, or works intermittently is often a sign of a worn-out motor drawing too much current or failing internally.
• Clicking or Grinding Noises: A clicking sound when you press the switch, followed by no movement, often means the motor is receiving power but is seized internally. A grinding noise could indicate stripped gears within the motor's gearbox or an issue with the seat track itself.
• Ventilated Seat Not Blowing Air: If you can hear the fan running but feel no air, the air duct may be disconnected. If you hear no sound at all when activating the function, the blower motor itself (e.g., 85860-33040) has likely failed.

Diagnosing the Problem: A Step-by-Step Guide

Before spending money on parts, follow these steps to pinpoint the failure.

1. Check for Obstructions: First, use a flashlight to thoroughly inspect the seat tracks under the seat. Coins, pens, and other debris can jam the mechanism and prevent movement.
2. Check the Fuse: Consult your owner's manual to find the fuse for the power seats. If both front seats don't work, a fuse is a likely culprit. If only one seat (or one function) is out, a fuse is less likely but still possible.
3. Listen for the Motor: In a quiet environment, press the switch for the failed function. Do you hear a faint click or a hum? A click suggests the switch and relay are working and sending power to a seized motor. Complete silence points towards a bad switch, a wiring issue, or a completely dead motor.
4. Test the Switch and Motor: This is a more advanced step. It involves using a multimeter to test for voltage. Unplug the connector at the failed motor. Have a helper operate the switch while you test the connector's terminals for 12V power. If you get 12V at the connector, the switch and wiring are good, and the motor is bad. If you do not get 12V, the problem is upstream (the switch, a module, or wiring).

Buying a Used Seat Motor: What to Look For

Purchasing a used OEM seat motor is a great way to save money, as new assemblies can be extremely expensive. However, you must be a careful shopper.

• Match the Function: Are you buying a slide motor, a recline motor, a lumbar motor, or a ventilation blower? They are not interchangeable. Verify the seller's description and compare the photos to your original part.
• Match the Part Number: The single most important step. If possible, remove your old motor to find the part number stamped on it. Match this number exactly. Do not trust a fitment guide that only lists year, make, and model.
• Verify Memory/Ventilation Options: Double-check that the donor vehicle had the same options as yours. Ask the seller to confirm if the part is from a memory or non-memory seat. Look at the electrical connector in the photos—does it match yours exactly?
• Physical Inspection: When you receive the part, inspect the plastic gear for any stripped or broken teeth. Check that the electrical connector is not cracked or damaged. Ensure the motor's shaft can be turned by hand (it will be difficult due to the gearing, but it should not be seized).
• Why Used OEM is a Good Choice: For a part like this, a used original equipment motor from a low-mileage vehicle is often a more reliable choice than a cheap, new aftermarket part. The quality of the materials and manufacturing of the OEM part is typically higher.

Cost of Replacing a Lexus Seat Motor

Costs can vary significantly based on which motor has failed and who does the work.

Known Issues, TSBs, and Recalls

As of early 2026, there are no widespread recalls or Technical Service Bulletins (TSBs) from Lexus or NHTSA specifically for the seat movement motors in the 2014-2025 IS, RC, and GS F models.

There was a Customer Support Program (L-SB-0040-19) for an unrelated fuel line rattle on some 2016-2018 models. Another program covered A/C servo motors in the dashboard, which are not related to the seats. Always check for the latest information using your vehicle's VIN on the NHTSA or Toyota/Lexus owners' websites.

Frequently Asked Questions (FAQ)