Hobie Adventure, pedal kayak - rudder jammed

I own a Hobie Adventure pedal kayak.
I don't recall "Island" being in the name when I bought it in 2008.
Something is jammed or fouled where the tiller lever to the front left of the seat will not move to steer the rudder.
When lowered, the rudder can not be moved right or left by hand or by tiller.
The "raise & lower the rudder" lever to the right rear of the seat works fine.
I can't locate the lines inside the hull.
How are they accessed?
Is there a cam or pulley somewhere that has come to grief?
Thanks for your help.