Tap a category to read its complaints. One report may name several components.
When problems were reported
Mileage at the reported incident
Limited mileage data: 3 of 3 reports include usable mileage. There isn’t enough coverage to show a useful chart.
NHTSA’s mileage field refers to the reported incident, not necessarily the filing date. This shows report counts, not the likelihood of a failure.
What to inspect
Issues worth paying extra attention to based on owner reports.
Electrical System. Review the 2 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
Vehicle Speed Control. Review the 1 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
NHTSA owner reports · September 18, 2026 snapshot.
0 crash reports1 fire reports0 injury reports
What owners actually said
3 reports
212,000 miles · Oct 29, 2009
Electrical System
ENGINE WIRING HARNESS FAILURE, MULTIPLE SYSTEMS AFFECTED. CAR WILL SPUTTER, STALL, NOT RESTART. HAPPENS WHILE GOING DOWN THE ROAD, TURNING CORNERS, COMING TO A STOP, WHILE TRYING TO ACCELERATE FROM A STOP.... THE ENGINE WIRING HARNESS HAS BARE WIRES ALL OVER THE PLACE. MB REFUSES TO ACKNOWLEDGE THAT THERE ARE PROBLEMS WITH…
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ENGINE WIRING HARNESS FAILURE, MULTIPLE SYSTEMS AFFECTED. CAR WILL SPUTTER, STALL, NOT RESTART. HAPPENS WHILE GOING DOWN THE ROAD, TURNING CORNERS, COMING TO A STOP, WHILE TRYING TO ACCELERATE FROM A STOP.... THE ENGINE WIRING HARNESS HAS BARE WIRES ALL OVER THE PLACE. MB REFUSES TO ACKNOWLEDGE THAT THERE ARE PROBLEMS WITH THESE CARS, ALTHOUGH I'VE SPOKEN WITH MANY MERCEDES OWNERS WHO HAVE THE SAME TYPE OF PROBLEMS. CALLS TO MERCEDES BENZ NEVER GET ME ANYWHERE. THEY ARE RUDE AND ONLY SAY THAT THEY HAVE NEVER HEARD OF ANOTHER BENZ WITH AN ENGINE WIRING HARNESS PROBLEM BEFORE. I CANNOT DRIVE THIS CAR, PERIOD. I WOULDN'T DRIVE IT TO THE CORNER FOR MILK EVEN IT WOULD START AND RUN CONSISTENTLY. THE WIRING HARNESS WAS MADE WITH "BIODEGRADABLE" INSULATION ON ALL THE WIRES. WHEN CAN I EXPECT THE AIR BAGS ON MY NEWER MERCEDES TO FAIL DUE TO SOME TYPE OF "BIODEGRADABLE" MATERIALS BEING USED? *TR
NHTSA ODI #10290278
138,000 miles · Aug 5, 2007
Vehicle Speed Control
WHILE DRIVING, MY 1991 500SL CONVERTIBLE FOR NO APPARENT REASON WILL NOT ACCELERATE AND THE ASR LIGHT COMES ON. IF I SHUT DOWN AND RESTART IT GOES AWAY BUT WILL COME RIGHT BACK IF I GOOSE THE GAS AT ALL. THIS HAPPENS A LOT! LOOKS LIKE THE SAME PROBLEM MANY PEOPLE ARE HAVING WITH 91-96 VARIOUS MODELS WITH THEIR WIRING HARNESSES.…
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WHILE DRIVING, MY 1991 500SL CONVERTIBLE FOR NO APPARENT REASON WILL NOT ACCELERATE AND THE ASR LIGHT COMES ON. IF I SHUT DOWN AND RESTART IT GOES AWAY BUT WILL COME RIGHT BACK IF I GOOSE THE GAS AT ALL. THIS HAPPENS A LOT! LOOKS LIKE THE SAME PROBLEM MANY PEOPLE ARE HAVING WITH 91-96 VARIOUS MODELS WITH THEIR WIRING HARNESSES. *TR
DURING THE REMOVAL AND INSTALLATION OF THE AIR FILTER HOUSING WHILE SERVICING THE VEHICLE, IT IS POSSIBLE TO MISROUTE THE PREFORMED VACUUM HOSE AND DAMAGE THE CHECK VALVE IN THE VACUUM HOSE. IF THE CHECK VALVE IS DAMAGED, LOSS OF SUFFICIENT BRAKE POWER ASSIST WILL OCCUR.
Consequence & remedy
Consequence: LACK OF SUFFICIENT BRAKE POWER ASSIST WILL INCREASESTOPPING DISTANCE AND COULD RESULT IN A VEHICLE ACCIDENT.
Remedy: REPLACE THE PREFORMED VACUUM HOSE WITH A NEWLY DESIGNED PREFORMED HOSE WITH A RELOCATED CHECK VALVE WHICH WILL ELIMINATE THE POSSIBILITY OF THE CHECK VALVE BEING DAMAGED.
Model-level recall history does not show whether a particular VIN is affected or has received a repair. Check a VIN with NHTSA ↗
NHTSA investigations
0
No exact-year investigations in this snapshot.
1991 Mercedes Benz 500SL Problems, Complaints & Recalls | Skip That Year
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