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A few things may have happened. The wiper arm may have come loose, stripped, or there is a problem with the linkage.
What I want you to do is first, confirm the nut holding the arm to the wiper transmission is tight. If it is, remove the wiper arm. Here are the directions for removal. The attached pics correlate with the directions. Also, you will see how to access the nut to confirm it is tight. Once you remove the arm, check it to see if it is stripped where it mounts on the transmission. Also, if it isn't stripped, with the wiper arm off, turn on the wipers and see if the transmission is moving.
WIPER ARM REPLACEMENT
1. Mark the wiper park position on the windshield with a suitable non-permanent marker.
2. Remove the cover from the wiper arm nut.
3. Remove the wiper arm retaining nut.
4. Remove the wiper arm from the wiper transmission drive shaft.
If the transmission doesn't move with the arm off and wipers on the linkage under the cowl at the base of the windshield may have come off. The wiper motor is mounted on the firewall under the hood. When on, it turns the linkage which is attached to each wiper. There is a ball joint connection at each side. See pic 3. It shows the joint being removed with a special tool. That may have come apart.
Let me know what you find so I can better help. Also, I will tell you that often times the wiper arm strips and needs replaced. You will know once it is removed. Regardless, I'm hoping it just came loose.
Take care and let me know if you have questions.
Images (Click to enlarge)
Saturday, April 27th, 2019 AT 9:57 PM