Make sure both wipers are in the "parked" position at the bottom of the windshield. Ensure each wiper blade is not frozen to the glass, and the windshield is clear of ice and snow. If the wiper arm still has the plastic nut-cover, GENTLY pry the plastic cover with a screw driver and lift it away from the nut. Be careful, if the outside temperature is below freezing, you risk shattering the plastic cover (BTDT). Use a 13mm wrench to tighten the nut on the passenger side, replace the cover, and "test" the wipers. Good luck.