I could see where the bad grounds could cause a problem, and cause all sorts of strange things to happen, but given the number of times I personally have seen the wire connection under the battery fail, I wouldn't make another move with unwrapping the bundle of wires and check the connections.

At this point, I'm 3 out of 5 Dakotas (90-96) that have had a bad connection. The other two I pulled apart and checked. When you locate that connector with 5 or 6 wires connected to it (some are pink wires, some are blue wires), give each wire a good tug. If its good, nothing will happen, if its bad, the wire will break. Those wires at that connection are 22 gauge wires, you can not break a good 22 gauge wire with your hands (or pull them out of a good crimp connector) each wires would start to cut through your skin and still not break. Gene