I have a 1991 JCB 525-65 I bought a short time ago. The symbols on most of the controls are wore off. The colum lever on the right side of the steering wheel has no marking on it. I belive up and down is for the dimmer on the lights. There is a push button on the end and the lever rotates to 4 different positions when you turn it. Nothing on this lever does a thing so far. Does anyone know the proper functions of this contol ?