Mercedes V Klasse electric seat issue

Weak battery is a prime suspect with these systems. Modern cars are ridiculously sensitive to voltage drops. But before you throw money at a new battery, have you checked the simple stuff? Specifically, I'd want to see if the seat wiring harness is properly connected under the seat. They can sometimes get kicked loose. Also, a proper diagnostic scan should give you a specific fault code. What was the exact code? That'll point you in the right direction much faster than guessing about the seat motor or anything else for now. The power seats draw a fair bit of juice so a low voltage situation would definitely affect them. Seat adjustment issues are common with a discharged battery.

Okay, thanks for the quick reply! I did have a quick look at the seat wiring underneath, but didn't see anything obviously disconnected. The fault code... I'll have to check again, it was something generic like 'seat adjustment fault'. I'll get the exact code tomorrow. If the wiring looks okay and the code is still vague, is it worth testing the seat motor directly, or am I barking up the wrong tree?

Hold off on tearing into the seat motor just yet. That's rarely the culprit. The generic code suggests a power or communication issue. A proper diagnostic tool should give you a more specific code. Check all the fuses related to the seat as well. Given that you suspect the battery, it's probably the best place to start. Get the battery properly tested. If it's failing, replace it and clear the fault codes. If the problem persists after a new, fully charged battery is installed, then you need to dig deeper. If the problem continues, you probably have to go to the workshop. Expect to pay around 290€ for repair costs.

Right, just wanted to let you know. You were spot on! I replaced the battery, cleared the fault codes, and the seat is working perfectly again! Seems the discharged battery was causing all sorts of problems. Thanks for the advice, you saved me a lot of time and potentially unnecessary expense.