Went though this with my 93 300E, flickering lights when depressing the brakes. Also my light out indicator would stay on. I tried differnt things as I was determined to solve the problem. Replaced all the bulbs, later replaced the stop light switch, replaced the headlight switch, played with the ground wires numerous times. One day my wife was driving away in the dark and noticed tha the left light assembly was dim. This was a new development. Took out the light housing, checked wires and connectors inside but made no difference. Bought a used light assembly and fixed the problem. MB doc is correct, it is a ground problem, but I could not find it without replacing the light assembly. All is good now. Hope this helps. Bill

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87 560 SL
93 300E 2.8
91 300CE-24