94 Dodge B250 Wiper motor help please!

I am having a problem with wiper motors going out on my van. I replaced the motor 3 times with new ones so far and can not figure out what is happening. The fuse has been fine until recently when the wipers stopped in the up position during a rain storm, then it finely blew.
Can somebody please help! I'm out of ideas of what could be causing the motors to blow.
Thank you
Quickdrawrob69

The motors you're installing could be of low grade (such as rebuilt units).

That aside, I would look at the linkage and arm pivots for places where it might be binding up. Binding linkage or arm pivots will load the motor down, causing it to overheat and fail prematurely.

I would look for wiring problems bad connections or corroded connections at any point, can cause high resistance and insufficient voltage to the wiper motor. Low voltage will cause the motor to over heat and burn out. Take a volt meter and check the voltage at the terminals during operation. Any thing less that 12 volts can put the wiper in a strain. Pay particular attention where the motor leads wwires go. You may even end up running a separate ground directly from the motor to the battery negative post. Also, the wiper motor switch wiring can have corrosion.
Good luck
bigbaribob