You might consider putting an in-line fuse in your jumper, just in case.

It would also help troubleshoot what the issue is. If it pops a 10A fuse, then there's something definately wrong and you can go from there.

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A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.