I recently purchased a 96 Ranger XLT 4 Cyl Manual, only paid 2400, only has 95,000 miles on it. Unfortunately the wipers don't work. I have done everything but blow the truck up to fix it. I have replaced both the motor and the multi function switch, i have taken a test light to the fuse box, the relay box and the motor plug, all tested positive. I used a volt meter and found that the plug is recieving and 12 volts required to turn the motor, yet the motor does not function, I am positively at a loss at what to try next, any ideas?

Might not be getting a good ground. connect the test light to the b+ of battery and test the body of the wiper motor, then the connector for the ground wire. good luck