I am going to refer to a similar issue with my 89 5.0 Mustang and the salt and pepper shakers.

The computer and electrical connectors on my Mustang for the motor are at the back and are black and white, hence salt and pepper. The white connector was causing similar issues with my Mustang as you are having with your van.

Check the electrical connectors as well, I cleaned them up and put a light coat of dielectric grease in to prevent further corrosion.