u/AdAway2724

hello guys is anyone car electrician here ? or anyone who knows how to read diagrams can you help me to find possible issue. I’ve seen two hours already and I can’t find what’s logical solution it can be I believe it’s high resistance but where? maybe I’m missing something and I need fresh look

so question is: the left rear signal lamp is dim when operated, the right signal operates normally. when stop lamp switch is depressed lamps operate normally.

thank you