It's hard to say without knowing what dump system you have
It shouldnt be electric unless someone has put a more modern dump hoist on the truck.
Chances are it is a PTO driven hoist which runs off the transmission. If it is there should be a knob on the dash or another lever which operates the PTO, the big lever in the floor is what makes it go up & down.
All with the transmission in neutral of course.
Got any pictures?
