I finally got a chance to dig through one of the books a customer brought me to use to work on his Liebherr 952 shovel. It's a factory school/training manual and shows the hydraulic schematics for all of the machines in that series (ie 902, 932,942, etc). It does show that the 932 has a solenoid valve that turns off the pilot control pressure. Typically this would be what the lever beside the seat activates. Unfortunately nothing in any of the books tells anything about the switch that turns it on or anything. That said, to find the valve, first find the accumulator that lets you lower the boom if the machine dies, and trace the line coming off of it. Based on what the diagram shows the solenoid valve is the only place that line goes. Once you find the valve see if you have voltage to the coil, and if not jumper voltage to the coil and see if things start working. If so you'll at least know where the problem is to at least start back tracing to find the actual electrical problem causing everything to not function.
Any more questions feel free to ask. It might take me a day or two to get time to search the manuals but I'll be glad to help any way I can.