126 headlight burn out
 

I have a 1982 300sd, The headlights keep burning out, I took it to the shop they said that I should replace the battery and the alternator. After doing that it worked for about a week then the lights burned out. Has anyone seen this type of problem? This problem is with both head lights high and low beam. I have checked the four related fuses. They are fine.

At this time I am thinking that it has to be something common to the all the headlights. Is there an overvoltage relay that protects the headlights?

Running sylvania H6054, sometimes the feliments are shartered. When they go out, they get brighter and then dimmer then they burn out.

Check your relays and fuses....

You may have an electrical sort.... Inspect the wire harnesses and plugs that connect to the lights

Over the years, in various cars, incuding, but not limited to MBs, I've had a few headlights "pop" from bad voltage regulators. See what voltage you're putting out at >2000 rpm.

Checked voltage at battery
 

I checked the voltage at 2000 rpm and it was at 14.37 volts.

Checked the power at the headlights
 

Checked the for fuses they check out ok. Checked the power at the headlight plug, and it was at 12 volts.