Cat 299C – No lift with control sticks, however aux toggle lifts loader???

Hello, My Cat 299C has lost all lift activation when utilizing control joysticks (both patterns). However for some reason when activating the aux rocker switch on the right joystick it result in the loader lifting, then instantly dropping after the switch is returned to normal. Any ideas on what could be causing this or where to start on diagnosis? S/N JSP00917