What are the reasons for a Mercedes starter being at a critical point?

[Tyra]

Mercedes starter being at a critical point can be attributed to the following reasons: Battery depletion: Most vehicles are used for short trips, and the battery is often not fully charged. If the vehicle is not used frequently, it can easily lead to battery depletion, causing the Mercedes starter to reach a critical point. Unauthorized modifications: Unauthorized modifications to the vehicle can easily result in power depletion. Additional electrical installations may lead to excessive discharge, causing the Mercedes starter to be at a critical point. Internal malfunctions: Faults in the door control computer or other internal vehicle issues can cause the Mercedes starter to reach a critical point.

[Willow]

Speaking of Mercedes starters reaching their limits, I've seen way too many cases in my over 20 years of car repair. The most common issue is the battery not holding up. Mercedes require high starting current, and after 4-5 years of use, the battery's internal resistance increases. When voltage drops below 11 volts, the starter just clicks without turning. Oxidized wiring connections often cause trouble too, especially that white frost-like corrosion layer on battery terminals - current can't get through at all. Then there's the wear on the starter's carbon brushes - when they're worn short, you get intermittent contact and unreliable operation. I remember last year an S-Class owner complained about delayed starting - turned out the ground wire bolt was loose by half a turn when we took it apart. All these problems push the starter to the brink of failure. My advice: first test battery voltage, then check wiring connections, and only as a last resort disassemble the starter for inspection.

[DiAlexis]

Last month, my Mercedes-Benz E-Class experienced starting difficulties. Every time I turned the key, it made a clicking sound but the engine wouldn't crank. I took it to a specialist repair shop, where the mechanic said these were classic symptoms of a starter motor in critical condition. They first tested the battery voltage - during cold starts it dropped to only 10.2 volts, which couldn't power the starter. After checking the wiring, they found some oxidation on the battery negative terminal; cleaning it helped slightly. The final diagnosis was excessive wear on the starter motor's carbon brushes, which was resolved by replacing them. Actually, poor contact in the solenoid switch can cause similar issues with intermittent current flow. Now during every maintenance service, I have the mechanic check the carbon brush thickness, since replacing the entire starter motor would cost several thousand yuan.

[Duane]

There are generally three common causes: the battery is aging and has insufficient voltage, causing a severe voltage drop during startup; the starter motor's carbon brushes are worn or the solenoid switch contacts are burnt; or there is poor electrical contact. During inspection, first use a multimeter to measure the battery voltage—if the starting voltage is below 9.6V, it's definitely a battery issue. Next, check if the starter's power supply wires are loose, especially the thick wire from the battery positive terminal to the starter. If the motor is removed, replace the carbon brushes if they are shorter than 5mm. Mercedes-Benz starter solenoid switches are prone to poor contact—if you hear a clicking sound, it's acting up. Also, don’t overlook corroded ground wires, as they can cause the same problem.