never seen one m,be nice to see the install manual....
since you say 'wiring and hydraulic' , I'll assume similar to 99.44% of all 'dump trailers'....12v DC motor drives pump, control valve to direct oil to cylinder ?
so simple questions
1) does the motor actually spin ?
2) did you put hydraulic oil in the reservoir ?
OK.. finally found this..about 10 versions of '850s' here in Canada, .though listed as 'electric' not 'electric/hydraulic' BUT... #060 looks to me like a totally self contained motor/pump/reservoir/cylinder so does THIS look like what you have ? page says it's a $4000 Canadian price !
If 'pump' doesn't make a noise, see if there's an inline fuse holder missing the fuse or machine's 'fuse block' doesn't have one ??
Without the install manual I'm guessing but it seems like a very simple unit.