Batteries are not the best, but have been replaced in the past, never drop below 36V. Power steering works and all the hydraulics, The MR, MF, MS do not engage. I'm trying to understand the testing sequence on how to start the diagnosis. Should i start with the Anode-cathodes? or the main or sub thruster. I don't understand how the flywheel Diode"s work. Any help would be appreciated, I've had two forklift company's out and neither one tested any of the components.

Your symptoms sound like a battery problem. So start with the battery, water, charge (assure charger output is correct) check gravity and if ok load test when fully charged.