i found a loose ground as i had most of the wires out recently to put ferrules on the wires going to amp. Is adhesive lined shielding foil tape worth anything?
one of them is a MT-1000 (700@2ohm), the other is ZD-750.4D (400@4ohm). i got a second because my car has electric power steering and i wanted more reserve capacity. It starts like a champ in -20 despite both those batteries being at least 10 years old.
edit; i'm going to remove that ground splice, going to sand the paint off of the bracket where the ground attaches to, and possibly redo the amp mounting to stack them vertically instead of beside eachother.