That doesn't make sense. Dead batteries cannot be accurately evaluated. If the battery were not dead then the van wouldn't need a jump to start. It sounds to me like you have a dead or junk battery and also have a charge system problem. If your alternator tests good then the next likely thing is the alternator harness. Did you check that as instructed earlier? If not, remove it from the van and test the wires for continuity. Do a visual on the smaller wires where they go inside the round 3 position plug. If there are any questionable connections replace the harness. They are still available through Toyota. Good luck. Tim

PS: Based on what you've said so far it doesn't sound like a fusible link problem, but at this point I think you should inspect those too.........just in case. Here is a good thread that talks about those in detail: https://www.toyotavantech.com/forum/...le-link-thread