There should be a switch on the underside of overhang to the left (driver's side) of the pin box.
BTW - welcome to the forum! You can create a signature block with your RV and tow vehicle information (see mine below). That way you won't have to repeat that information whenever you post or ask a question - and others won't have to ask. You can create a signature by going to:
Forum Actions (on menu bar) -> Edit Profile -> Edit Signature (under My Settings on the left)
Rob