Have you tried to move the van again after it left you stranded? After sitting, if it will move for a short period and then stop again, the filter is likely plugged. Plugged filter means the trans needs to come apart to find the cause of the debris in the filter. Even with the electronic controls dead the trans will still move but not shift. Easiest thing would be to drop the pan and look to see what has settled to the bottom and is stuck to the magnet and go from there.