What liftman said is true however he is talking about the hydraulic motor for running the tilt, up down, and side shift functions. That is a different motor than the one that runs the hydraulic power steering. And then there is yet one more motor the big one that is for moving the entire truck forward or backwards. To test your battery without frying your board if you are eager just unplug the logic board and then you can manually push the contators in, that are in the photograph you took and it will activate either the hydraulic pump for the main fork functions and the other one will activate the pump that runs the steering. When you let go the motors will shut off. On my trucks there are micro switchs on the levers that turn the fork function pump on and off when you push a lever so the pump is only on when you move a lever then shuts off again. Power steering as I said before stays on as long as the machine is in gear and in your case probably when you push the pedal. Let us know how it goes. And my Clarks do not have a safety switch in the seat. If you do have one though just unplug it and put a jumper on it to bypass it to rule it out as being a problem, however id be surprised if yours has one lookin at its age.