![](http://photos1.blogger.com/blogger/1224/1926/200/IMG_4442.0.jpg)
I was able to determine the vacuum was not the issue, evidenced by the hissing sound from the tube that attached to the wiper motor. At the advice of a member of Pilothouse.com, I removed the wiper motor and will be sending it to Bob Ficken at www.wiperman.com, who specializes in reconditioning these devices.
Note: it is highly recommended that the vacuum tube be constricted while driving the truck until the new motor is mounted and all is reconnected.
To be continued....