The wipers on my 2001 Chevy Astro cargo van quit working completely.

It would be not very possible to instruct you on how to start to finish perform testing on any component of your vehicle regardless of being your wipers at all. You need to have some technical know-how and some hands on experience along with proper tooling, test equipment, and shop manuals for reference. Needless to say, this forum can't really instruct you on that level. The wiper system of the vehicle consists of a switch and motor basically. You also have wiring and connectors in between, as well as circuit protection. In simplest form, you check for power and ground at the motor with the switch in the on position and the ignition on. If you have power, and the motor doesn't respond, then the motor is a concern. If you have no power then it's possible that the switch or wiring could be of concern. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops