D5c not moving correctly

I have borrowed my friends d5c xl, I'm not sure what year model but it is a joystick model. The problem is once you've been running a while the drive controls almost don't work. You can move the joystick a little and nothing. If you push it all the way in the direction your wanting to go it will barely move. Has anyone else had similar issue? One thing I've noticed is the "park light" always stays on. My friend says it has done this since he got it. Could this be doing something to the...

D5c not moving correctly

D5c not moving correctly