On my 1994 Mercedes w124 E320 wagon both headlights not working. Rear brake lights: left side working, not on right side. Both turn signal lights works in the headlights section, turn signal light working on left side (driver) near the brake light rear of the wagon, turn signal not working on the right side (passenger) near the brake light rear of the wagon. Both Fog lights (yellow) on the the front headlights(Left and right) working when turning on the lights. Checked the fuses, (black box inside the engine on the driver side). All fuses checked O.K.
Control module in the fuse box has failed?
Must be some kind of "electrical gremlins" going on here. Any ideas? I am practically stumped by this rather unusual issue. Thanks to all for reading this post.

Check the headlight switch. Mine did something similar and replacing the switch fixed it. Also check the fuse connection for any corrosion. Give them a scrub down

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1993 e300
1995 e320
1994 e320
2006 s500 4matic
2004 Jeep wj overland
2001 Ducati 748
2004 Honda shadow aero

speednjay, Thank you for your quick response. I appreciated it. I never had this issue before. Will follow up with an update soon. Thanks, again.

Could be both bulbs burned out due to bad voltage regular in alternator

I checked both holders for the bulbs, inside the tail light and has the cable and connector to the body wiring harness. The Mercedes-Benz part number on this is 124 820 18 77 and replaces the older part numbers 124 820 1677 and 124 820 17 77. Tail Light Bulb Socket Assembly for 1987-94 Mercedes W124 - 300TD, 300TE Wagon, 124 820 18 77

On both Tail Light Bulb Socket Assemblys, both of them were loose and not showing the lighted tail light on the reflected tail lights. One light bulb on each of the tail light bulb socket assembly was burned out. I replaced them both. I then taped the tail light bulb socket assembly to the reflected tail lights inside the wagon and secured its holding place.

Both tailights top red color means applying the brakes and both lights lighted up and came on and worked. However, when I turned on the lights (both front headlights were not working) above the parking brake pull handle, only the bottom left rear (driver's side) red color tail light was on. The passenger side rear tail light bottom red is not.

I switched both tail lights to see if there is any difference and so far it is still the same. I suspected the light turn on switch above the parking brake handle is worn out, possibly causing the failure of the headlights to turn on and the right rear passenger side tailight bottom red light as well. Will continue to investigate further on to replace the light switch to determine whether or not that will make a difference. Any other ideas out there to comment/advice on this troublesome issue? Thanks to all for reading

nulu Thank you for your comments. I checked the voltage regulator using a tester. Voltage regulator in the alternator is fine.