Problem: Over the past two days, my car has abruptly and completely stopped dead. Two occasions were in parking lots outside my office, one while approaching the very same area a couple minutes ago. The engine will be running just fine, when all of a sudden, the entire electrical system just shuts off. So far, this has been seen to be caused by two distinct events: Turning on any electrical device, or a sudden physical jolt (i.e. the ramp to my parking lot, consumer of bumper paint and foglights).

Solution: Shake the battery. It worked! It causes the car to have power again...but this makes no sense!

Why should shaking the battery cause power to return? One would suspect a bad ground lead to the chassis, but it is secure (though it could use a cleaning). Another possibility could be connections around the battery, but even holding these steady and having another person nudge it.

I replaced the battery, and the problem still persists. The only observations was a substantial crack on the positive battery cable, but it did not appear to be exposed to the point of risking a short.

I'm lost.
--
1984 240 DL, 1988 740 GLE, 1990 740 GL1993 850 GLT