Sorry for the title but I could not help it. I just got my 1983 300Sd out of the shop about a week ago after not having it for the past month. It got a valve adjustment and a new starter. The car starts and runs fine after the work. I just drove back to school today after being away for a few days for spring break. I have a subwoofer in my trunk. It was unhooked during the winter because before the new starter, I needed all the battery i could get. All i did was connect the positive lead from my speaker amp to the positive lead on the battery. There is an inline fuse from the battery to the amp and another fuse on the amp itself. I turned the key to the glow position and waited as normal before starting. The subwoofers came on. I turned the key to the start position and everything went dead!! no glow no dome light, nothing. I checked all of the fuses of the car itself and the amp wiring etc. I unhooked the positive lead for the amp and tried again, nothing happened. I then unhooked the positive lead of the whole battery tried again and the car had power, dome light glow plugs etc. I tried to start again and the whole thing died again, each time after it ties, if i so much as wiggle the positive lead on the battery i get power but the same thing happens each time it starts. I am desperate here and this is the only place I know to turn. thank you

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W126 1983 300SD 286,000 miles and ticking
Baby blue exterior Grey MB tex
Recent work:
Replaced air cleaner mounting brackets and heat shields
Replaced alternator, fan and power steering belts
Replaced positive battery terminal
Replaced negative battery terminal and cord
New Duralast Battery

My car needs work.