Mercedes B Klasse Seat Heating Issue

Ah, seat heating woes! I feel your chill! I had a similar experience with my old Volvo V70, though it was a diesel. The seat warmer refused to warm, and it turned out to be a break in the heating element within the seat itself. Did you check the wiring harness under the seat? Is there a temperature control module involved in this system?

The wiring harness appears intact upon visual inspection. No obvious signs of damage are present. Regarding a temperature control module, is this typically a separate component, or integrated within the seat heating control unit? Are these thermal sensors prone to fail?

Typically, yes, there is a dedicated temperature control module, or at least a thermal sensor that feeds back to the main control unit. It prevents overheating. However, if the heating mat is indeed faulty, the sensor will not receive any temperature change to report. I would strongly recommend taking it to a qualified workshop to diagnose the specific cause of the error. It is likely the seat heating element needs replacement.

Thank you for the insights and suggestions. I have scheduled an appointment with a qualified workshop. The diagnosis confirmed the defective seat heating mat. Heating repair has been completed according to the provided estimate. Appreciate your help!