Which parts fail
Components named in complaints (seat frames, recliners, heated seats and seat tracks).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2002 Mercedes-Benz C320 owners, lightly cleaned up (personal details are redacted by NHTSA).
Tl* the contact owns a 2002 Mercedes Benz C320. The contact stated that the battery was drained after the vehicle was parked and turned off. The vehicle failed to restart. The vehicle was taken to an independent mechanic to be diagnosed. The contact was informed that the driver's side seat module was defective which caused the battery to drain. The module was unplugged to prevent the battery from being drained. The manufacturer and local dealer were not notified of the failure. The failure mileage was 114,000.
The car parked in the garage overnight and the morning I had an emergency at the business and could not start the car. The battery was totally drained. Had it towed to the shop to be diagnosed that it was the front driver side power seat that has drained all the energy from the battery even when the car is not running. The power seat is now continuously excessively drain the battery even when the car is not running. The consequences are that the car is not trusted to be able to start in an emergency situation when the car is needed for transportation. The car has very low mileage on it. The power seat has been rarely used and it should not fail for having been idle/not used for the length of time that I have own the car. I am the original first time owner of the car and I hardly have to adjust the power seat. …
My vehicle would not start, so I received a jump, two days later when I did not drive the car it would not start received another jump and replaced the battery. Did not drive the car from 7-4 to 7-8-07 and car would start. Went to Mercedes dealership on 7-9-07 and was told that it was a common problem on my car that the seat modules do not power down when the car is off and that it is draining the battery. Went to several Mercedes-Benz forum websites and found that there were hundreds of people having the same problem. Once the seat module are replaced for $1200.00 that the seat modules would continue to drain the battery and would have to be replaced again and this became a cycle. Please visit websites www.benzworld.org/forums or m-benzforum.com or type in google or yahoo mercerdes Benz forum and connect. Here you will see a list of people with the same problem.
I own a Mercedes Benz C320 and lately I've been experiencing some problems, few weeks ago, my car wouldn't start all of a sudden. I jump started and I noticed 2 faults .. ESP warning light and light sensor ,for some reasons something was draining my battery, I went and purchased a brand new battery and 2 days later it did the same thing again, I was told that it was a seat sensor that caused it,s o we unplugged the seats, everyting seamed fine for like 4 to 5 days,while I was driving,the car just came to a complete stop would not move,the engine light came on, I've come to realize that I'm not the only one with this problem, I hope the government would do the right thing by recalling those vehicles.
Both internal seat control modules have electrical fault. Test code 8e3l-k8nnq. Found 1.66 amp of draw (out of spec. Range) amp drop when disconnected: passenger side to: .1114 and driver side: 0.59 milliamps. 1/13 alarm sounds and battery dies. Technician replaces battery, but warns likely to happen again-many cases. 1/16 same problem. Car taken to other m-b dealership. Diagnosed as above. Replaced both modules 1/25. Dealership had trouble getting part due to unusually high volume for this repair. 18 modules gone or on reserve in one week in santa monica alone. Mercedes corporate office unresponsive. Carmax denies known fault, but reports customer with same complaint previous week.
I came out and my battery was dead without warning. I took the vehicle to downtown la motors(Mercedes Benz) dealer, where they explained that the seat control modules were staying on and causing the battery to drain. I subsequently had to unhook the seat controls and now I am unable to move my seats or steering wheel. They estimated that the repair would cost around 1500. Numerous customers have the same issue on the same vehicle, it is obvious that this is a manufacturer defect and not the fault of Mercedes Benz consumers.
Faulty seat controller of a Mercedes c32 amg, drains car battery overnight, causes new battery replacement and controller replacement (not cheap - appr $400). No new controller purchased from mb USA, just disconnected plug (moving seat is inoperable). I noticed almost all us Mercedes Benz vehicles with that body style (w203) have that issue. Sources: bay area dealerships, a repair shop and online forums.
Tl* the contact owns a 2002 Mercedes Benz C320. The contact stated that the vehicle failed to start. The vehicle was taken to the dealer where the technician diagnosed that the power seat module was draining the battery and as a result, it needed to be replaced. The manufacturer was not made aware of the failure. The vehicle was not repaired. The failure and current mileage was 81,000.
Tl* the contact owns a 2002 Mercedes C320. The contact stated he had to replace the battery in the vehicle several times. The dealer stated the seat controls for the passenger seat drained the battery and the seat control module needed to be replaced. The failure mileage was 89,000 and the current mileage 90,904.
At 45,000 miles front passenger seat started draining the battery. Dealer told bad control unit. Because of high cost of repair ($900.), it has been disconnected. The control unit was least utilized for the passengers seat. This should not have failed under 45000 miles use.
Seat complaints in other C320 years
Frequently asked questions
How common are seat problems on the 2002 Mercedes-Benz C320?
NHTSA has 23 complaints about the seats of the 2002 Mercedes-Benz C320, 34% of the model year's 68 complaints. The component named most often is front assembly › power adjust (2 mentions).
Is there a recall for 2002 Mercedes-Benz C320 seat problems?
No. NHTSA lists no seats recall for the 2002 Mercedes-Benz C320, though it has 3 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2002 Mercedes-Benz C320 seat problems start?
Half of the complaints with a recorded mileage happened before about 72,000 miles.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.