Try to make your own ground wire with jumper cables under the hood.
Use both leads to engine hoist bracket thats right up front and other two to the driver front bolt thats right by the headlight. Give that a try, easy test.

Mine wouldnt start one day and i was told to do that and it fired up. Not uncommon for the engine ground wire to corrode. I have a semi-permanent cable in the same way i just described on mine, been over a year and still going great.

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2011 35d