Mercedes SLC Diesel Massage Seat Not Working

I had a similar issue with my SLC. Before tearing apart the car, check the seat switch itself. The connectors can come loose or corrode. Try wiggling the connector, or use contact cleaner. If that doesn't work, it might be a deeper issue with the seat motor control module. Is the error message specific? Knowing the exact error code would help. Does the error clear, or does it come back immediately?

I wiggled the connector, but didn't try contact cleaner. The error code is B290071, which points to a general fault in the seat motor control circuit. It comes back immediately after clearing it. Was the error persistent when you had the problem?

B290071 sounds like a deeper issue than just a loose connection. Given that the error is persistent and you've already tried the basic checks, it's probably best to take it to a workshop. The diagnostic tool is pointing to a fault in the seat motor control circuit, and chasing electrical gremlins in a modern car can be a nightmare. The dealership can pinpoint the exact cause and repair it properly. My repair cost was around 95€.

I cleaned the contacts and it didn't fix the issue. I took it to a local shop and they confirmed it was a faulty connection and fixed it for around the price you mentioned. I appreciate the help!