Battery to engine block front lower passenger sideWhere exactly are the Big Three Grounds?
Rear engine block passenger to frame rail passenger side
Frame Rail to Firewall.
The last two are straps that often corrode.
Was just looking at a buddy's 95 last night and noticed his ground off the rear engine block to frame rail was missing. It had obviously corroded and someone had connected the corroded end back to a bolt on the frame rail and so was doing nothing.
It's a pig to get to on the rear engine block. A 48" cable directly from the battery to the frame rail will fix it. But as the jumper cable didn't make any difference I doubt that is an issue.