Wiper arms

1997 ford explorer, driver side wiper works but passenger side doesn't. How do I access the linkage to check it. How does the cowl come off. I can't figure it out. There's an access panel on the firewall for the driver wiper but not one for the passenger side. I need help. Thanks.

Raise up the little cover on the lower part of the arm and tighten the 15mm nut.