5inhisgrip5

My 96 Astro with a 4.3 will completely loose all power. With the battery cables on and tight, there is Zero power showing when a volt meter is placed on the positive and negative cables. Once I remove the Positive cable and re check the battery power it reads 13 volts. Once I attempt to put the positive cable back on I get sparks on the positive cable terminal. I have changed to top mount terminals 5-6 years ago with no problems. I have taken both cables off the battery and cleaned both to ensure good contact and each time I attempt to connect the positive cable it sparks. If both cables are in place there is absolutely no power to the van. The ground wire that goes to the radiator mount is both clean with no corrosion and tight. Any ideas???

5inhisgrip5

Took the alternator off and had it tested. It had an open circuit and was bad. Put a new one on and I still have the same problem. Could the problem be in the ground wires or straps from the block to the frame?