1994 Mercedes-Benz 129 Problems
Owner-reported complaints filed with NHTSA, grouped by component
Data refreshed
What this page shows
Everything below is an owner-reported complaint submitted to NHTSA about the 1994 Mercedes-Benz 129, grouped by the component NHTSA recorded on the report. These are not confirmed defects, and they are not recalls. NHTSA does not verify most reports before publishing them, and a category with more reports in it is not evidence that a part is defective.
Complaints are reports submitted by owners and drivers to NHTSA. They are not verified and do not establish that a defect exists.
Reports by component
Ranked by how many owner reports name each component category
- Electrical1100.0%
Percentages are of component mentions. A single complaint can name more than one component, so these do not sum to the total complaint count.
Each component in detail
What the reports in each category say, in the owners' own words
Electrical
Reports naming the electrical system — wiring, battery, charging, control modules, infotainment and electrical accessories.
From owner reports, verbatim
THE WIRING HARNESS, OF WHICH THERE ARE THREE, WAS CONSTRUCTED OF AN INSULATION CASE THAT IS BY DESIGN BIODEGRADABLE. THIS WAS A MATERIAL SELECTION DEFECT AND IS CAUSING GREAT EXPENSE AND PAIN TO OWNERS OF THESE CARS. IT IS ALSO DRASTICALLY AFFECTING RESALE VALUE OF THE CARS. UNUSUAL FOR A CAR THAT COST OVER $100K NEW. THEREFORE, THE OUTER CASE OF THE THREE HARNESSES DISINTEGRATES OVER TIME, AND EXPOSES THE INDIVIDUAL WIRES TO EXCESSIVE HEAT FROM THE 12 CYLINER MOTOR - THIS CAUSES THE INSULATION AROUND THOSE INNER WIRES TO CRACK AND DISINTEGRATE, AND OVER TIME LEADS TO FAILURES AND HAZARDS - AND DURING MODEL YEAR 94, 95, 96 - AND CASES ARE NOW BEING REPORTED FOR MODEL YEAR 1997 - IN THE SL600 MODEL - IT IS THE R129 CHASSIS AND IS KNOWN TO AFFECT OTHER CHASSIS THAT USE THE SAME 12 CYLINDER MOTOR. THE FAILURE RATE IS NEARLY 100%. IT IS NOT A QUESTION OF IF IT HAPPENS, IT IS A QUESTION OF WHEN IT HAPPENS. I HAVE CONTACTED MERCEDES ABOUT THIS, AND OFF THE RECORD, THEY ARE WELL AWARE OF THE PROBLEM - IT IS A WIDELY KNOWN ISSUE ON THESE VEHICLES, BUT THERE IS NO MANDATE TO CORRECT IT OR SO THAT IS WHAT I WAS TOLD. . THERE ARE MANY CASES LISTED HERE WITH THIS AGENCY WHERE ENGINE FIRES OR LOSS OF DRIVER CONTROL OCCURS AS WELL - PLEASE SEE OTHER CASES LISTED HERE. THIS IS A TRUE SAFETY PROBLEM. THIS HAS NOT HAPPENED TO ME YET, BUT I HAVE ENCOUNTERED THE PERFORMANCE PROBLEMS AND ELECTRICAL COMPONENT FAILURES. IT IS A VERY COSTLY REPAIR - BOTH FOR PARTS AND FOR LABOR, AND CAN RUN UPWARDS UP TO 8000 TO REPAIR. THE SYMPTOMS OF THIS PROBLEM ARE POOR OR INCONSISTENT PERFORMANCE FROM THE ENGINE, POOR THROTTLE RESPONSE, OR COMPLETE FAILURE OF THE THROTTLE BODY AND MASS AIR FLOW SENSORS. INCLUDING ROUGH IDLE, HESTITANT ACCELERATION, ENGINE FIRES, ENGINE SHUT OFF DURING OPERATION, FAILED ELECTRICAL COMPONENTS. *TT
Too few reports in this category for a page of its own — they appear in the full complaint list.
Higher-selling and older vehicles accumulate more reports. Counts are not failure rates and are not directly comparable between vehicles that sold in very different numbers.
Elsewhere on this vehicle
Data sources
- NHTSA Office of Defects Investigation — owner-reported complaints and the components recorded on them
Data on this page last refreshed .