In addition to standard used car shopping best practices such as examining vehicles for rust damage and having a mechanic perform an inspection, buyers shopping for a used Mercedes-Benz should inquire about the condition of the vehicle's electrical system as many Mercedes-Benz vehicles experience problems with these components. This is especially true for some S-class models built in the 1990s and 2000s. Purchasers of C-class and E-class vehicles should also inquire if the engine's balance shaft has been replaced.
Electrical problems are often reported in Mercedes-Benz vehicles, partially due to the large number of luxury features and the consequent higher complexity of the electrical systems in these cars. However, some Mercedes-Benz vehicles have design flaws that make electrical problems much more likely than in others. For example, the S-Class sedan sold from 2000 to 2006 has a valve that can easily become stuck open and admit rainwater into the vehicle, leading to damage to the vehicle's rear electrical system and fuse box as well as general water damage. Similarly, the 1994 and 1995 S-class can experience electrical failures due to loss of insulation from the central wiring harness.
While not as prone to electrical issues as the complex S-class, C-and E-class Mercedes-Benz sedans from the mid-2000s are prone to balance shaft failures. A balance shaft failure usually occurs at higher mileage and results in an expensive engine repair. Determining if a used car's balance shaft has already been serviced or replaced may save buyers the expense of dealing with this problem down the road.