GS massage seat failure

Interesting issue. I had a similar problem with the lumbar support on my old BMW 5 series. The symptoms sound identical – no response from the switch, and a corresponding error code. In my case, the fault was indeed a frayed wire where it entered the seat frame. Given your mention of cable harness issues, that could be a place to start. Does the Lexus switch illuminate when pressed, or is there a complete absence of any indication?

The switch doesn't light up at all. That makes me think it's a circuit problem. Since you had a similar issue with the BMW, how did you figure out exactly where the problem was?

Given the lack of illumination, I strongly suspect a complete break in the circuit. I started by visually inspecting the wiring harness where it flexes near the seat hinge. If you are not comfortable doing so, I recommend you take it to a professional workshop. It ended up costing me around 80€ in parts and labor, but the alternative was ripping apart the seat upholstery myself.

I appreciate you sharing your experience. I will heed your advice and entrust the diagnostic and repair procedures to a qualified technician. The anticipated expenditure of approximately 95€ appears a prudent investment to preclude any inadvertent damage to the delicate car upholstery. Thank you again for your valuable insights.