AI Damage1999 Mercedes-Benz S420 reliability: common problems
Owners of the 1999 Mercedes-Benz S420 filed 4 complaints with NHTSA, most often about electrical system and air bags. Details by component below, with sources.
Key figures
- Owner complaints
- 4
- involving a crash
- 1
What fails most often
- 1 Electrical system 75% of all complaints
- 2 Air bags 25% of all complaints
- 3 Electronic stability control 25% of all complaints
- 4 Latches, locks, linkages 25% of all complaints
- 5 Seat belts 25% of all complaints
- Electrical system: 3 complaints (75% of all).
- Air bags: 1 complaints (25% of all), 1 of them with a crash reported by the owner.
- Electronic stability control: 1 complaints (25% of all).
- Latches, locks, linkages: 1 complaints (25% of all).
- Seat belts: 1 complaints (25% of all).
Symptoms owners describe
How many of the 4 NHTSA complaints mention each symptom (automatic count from complaint text; one complaint can mention several).
Components owners complain about
| Component | Owner complaints | involving a crash | Technical service bulletins (TSB) |
|---|---|---|---|
| Electrical system | 3 | 0 | 0 |
| Air bags | 1 | 1 | 0 |
| Electronic stability control | 1 | 0 | 0 |
| Latches, locks, linkages | 1 | 0 | 0 |
| Seat belts | 1 | 0 | 0 |
What owners report
Short excerpts of NHTSA complaints in the original wording. These are owner statements not verified by NHTSA; personal data removed.
While driving, consumer was broadsided by another vehicle, however it was not stated exactly where vehicle was hit, subsequently the airbags failed to deploy and consumer suffered severe injuries.
The contact stated that he exited the vehicle through the passenger's side window. The vehicle was taken to mercedes-benz of danbury ([address], danbury, [ZIP]) and was diagnosed that the vacuum pump failed and needed to be replaced. The vehicle was not yet repaired.
The area that holds the brake lights keeps melting I have replaced them twice , seat belts lag and dot work I have had several problems with stabilization
The instrument cluster has almost totally failed creating a severe safety hazard. The dealer stated vehicles with this problem are being recalled. How do I receive a recall notice?
When owners complained
NHTSA complaints by filing year. The peak shows at what age the problems show up most.
Comparison
By complaint count this model year ranks 14,162 of 32,257 model years in the NHTSA data (top 44% most complained about).
On average one model year of the S420 has 3 complaints (4 years in the data). This year has 4, above average.
What to check before buying
- Electrical system. Scan all modules, test the battery and alternator, inspect connectors near the impact zone.
- Air bags. Check the SRS light, stored codes and airbag/curtain status after any impact.
- Electronic stability control. ABS/ESC sensors, steering angle, codes after suspension repair.
- Latches, locks, linkages. Door, hood and tailgate latches, especially near the impact.
Other years of this model
Questions and answers
What are the most common problems with the 1999 Mercedes-Benz S420?
Owner complaints to NHTSA most often mention: electrical system, air bags, electronic stability control. Total complaints: 4. The most frequent symptoms in complaint texts: airbags did not deploy (25%), seat belts (25%), windows, sunroof (25%).
How many service bulletins (TSB) were issued for the 1999 Mercedes-Benz S420?
NHTSA lists 0 manufacturer service bulletins for this year. A bulletin tells dealers how to diagnose or fix a known issue; it is not a recall.
Should I buy a 1999 Mercedes-Benz S420 from a US auction?
Owner complaints describe defects, not crash damage. Before bidding, check the components listed above and review the lot photos: VinWind builds a report of visible and hidden damage by VIN.
Other 1999 models
Read also
Sources: public NHTSA data (USA): service bulletins and owner complaints; YouTube: links to videos credited to their authors. Complaints are owner statements not verified by NHTSA, and describe defects rather than crash damage. Data updated 2026-11-06.