If the pedals are locked all the time, then start there. Air will not cause the pedals to lock. With the service run switch in the run position, I think the toggle switch is forward. With the key in the OFF position, watch the instrument panel as you sit in the seat. The panel should light up and go through a self test when you sit in the seat. If the instrument panel does not light up, raise yourself off the seat and flip the service/run switch in the opposite direction and then sit back down. If the instrument panel does not light up, then you are not getting power back to the instrument panel through the seat switch.......................If the panel lights up with the key off, then the seat switch circuit is working. After the instrument panel finishes the self test, there will be two lights lit on the panel, park and seat belt. Fasten the seat belt and the seat belt light should go out. If the light does not go out, then the circuit from the seat belt to the instrument panel is not working. All these initial tests are done with the key in the off position. With the seat belt light off then turn the key to the on position and the pedals should be free.............Even with the pedals locked you can still tell if the hydraulic pump is working by engaging the aux hyd by pivoting the top of the right handle up or down. If the hydraulic pump is working then the engine will pull down when the oil deadheads at the couplers...........Unless something is blocking the intake, even sucking air would not keep the loader from moving without having an oil mess from the loose or damaged hose.