wkd

I bought a CPO 2016 sl 400. The automatic hi/low beam feature does not work. I have had it into two different MB dealers. Both say that the system has no fault codes and should work. Unfortunately, they have not been able to duplicate the problem as the only way to experience the fault is by driving the car at night.
The auto setting shows up on the instrument cluster, but on a completely dark night on a country road away from any light source, the high beams will not activate. The only way to turn the high breams on is to switch too manual and use the stalk top switch between hi and low beams.
Does anyone have any insight into this issue?
Thanks

rorywquin

Deleted

Piperkid

Are you driving above 35MPH?
Auto does not work at low speeds.

rorywquin

From my user guide


Press the combination switch beyond the pressure point in the direction of arrow .

• The indicator lamp in the multifunction display lights up when it is dark and the light sensor switches on the dipped-beam headlamps.
  At speeds above approximately 25 km/h: the headlamp range is automatically controlled according to the distance to other road users.
• At speeds above approximately 30 km/h:
  • if no other road users are detected, the main-beam headlamps are automatically switched on
  • if other road users are detected, the partial main-beam headlamps are automatically switched on
• The indicator lamp in the instrument cluster also lights up.
• At speeds below approximately 25 km/h or when there is sufficient street lighting:
  • the partial main-beam headlamps are switched off automatically
  • the main-beam headlamps are switched off automatically
• The indicator lamp in the instrument cluster goes out. The indicator lamp in the multifunction display remains lit.

To switch off: move the combination switch back to its normal position or move the light switch to another position.

• The indicator lamp in the multifunction display goes out.

Pete Collie

I have a similar issue on my E500 (550) with a failing auto high beam.
During a very hot day (around 45 deg C, well over 100 Deg F) I jumped in the car, pushed the start button and there was an error message on the instrument cluster "Auto headlamps Inoperative" and the headlamps were turned on. No setting on the headlamp switch would turn them off. After around 20 mins of driving the cabin was a lot cooler and the lights turned themselves off. I have now noticed that the auto high beam is no longer working when driving at night. The lights come on when it's getting dark, but no high beam unless I switch the headlamp switch to manual and use the stork.

Zero errors when running a scan and the local dealer has no clue. They want me to leave the car with them to diagnose. (At that cost, I could buy another car)

Any ideas?

Pete
2009 W212 E500
Melbourne Australia

eddieo45

I've got to read the entire section in the manual but that excerpt rory posted is mind-numbingly confusing, at least to my early-AM partially numb brain. Thank goodness for Piperkid's simple summary. I was on a dark country road wondering why I couldn't get the high beams to stay on and now I know why. Oddly I didn't even think to pull the stalk back; I just kept toggling between the forward and back positions. I've posted before that even in the "headlights on" position (1:00 o'clock) they seem to turn off automatically in daylight, but I've read that the LED DRLs will not be on at night in that setting.....