Hello,
2 years ago i put new wiper motors into my truck for the same symptoms.

During warm weather, such as early fall, spring and summer, my wipers work great. No problems, no hiccups, exactly what you would want.

However this time of year (mid november - spring) it apparently gets cold enough to make my windshield wipers stop working. I flip the switches, nothing happens, even with the washer button.

The problem doesnt 'go away' when the truck warms up either.

This happened last week, it was very cold. however, we had a few warm days, and the wipers worked great on those days.

I am seeking some enlightenment here. how can i fix this?

 

Case in point,
wipers didnt work this morning when i took my daughter to school.
However with the sun out now, they are working at 9am.

 

I guess check to see if you are having power to the wiper motor when it is not working. Maybe I mean it's just crazy enough but when it gets cold my your ground contracts and loses connection but when warm it expands and make a connection. I'm just blowing smoke here but hey any things possible right?

 

Since I just noticed moisture in my instrument cluster (cracked windsheild) I would suggest the motors have moisture in them that is freezing in a critical spot that prevents movement. How it got in to new motors?????

Edit
It just occurred to me that they may have used a low quality lubricant inside the new motors and that this lubricant is freezing.

 

I would also check the regulator(not sure thats the name) its at the bottom of the dash near the gas pedal area kinda clipped behind the dash. I would also pull the connector off the control stalk and clean the contacts. ive seen some weird s**t happen from a dirty connector at the switch.

 

Did you figure it out AitkenSP?