Brewcrew,
If you had an Email address I could scan an send you fault finding chart for this fault, Dose this truck have an Earth leakage detector fit if not sure you will find it mount on steer colume under B.D.I. guage and hr meter.
1 Check Voltage at 1 Rec Terminal It should show Bat volts If not check power fuses and cables.
2 Check drive motor cables for open circuit also check contactors are closing correctly and making circuit,
3 Are the above checks correct. I f not rectifye cable or contact fault,
4 turn key switch on I rthink you may have done this part Check TB1 by six terminals and speed control dose the meter read between 3 and 4 volts if not replace logic card if yes depress S.C.U. note it is not necessaary to select Direction for this test. Dose the SCU fall to O If not check wiring to speed control wiring.
5 Check the Thermistor normal resistance of thermal protector is 120-150 ohms at 18*C when measured between PZ1 and PZ5 Replace if Faulty.
6 Test the current sensor a a short peice of bus bar with 2 wires attached to it book says it should have small resistance
it also says do not attemt to repair,
7 No 1 gate signal test.
1 set volt meter toDc range black lead of meter to No1 rec cathode, red lead to gate signal connection maybe blue and white wire.
2 Close keyswitch seat and hand brake switch dose voltage rise in relation to SCU depression. If not check all Z plug to all terminals on panel, Rectifye any open circuits if wiring checks out Ok fault lies in logic card. If voltage rises then no 1 rec is faulty.
All meter checks to be done in respectof negative,
Please make sure drive wheels are of the ground.
If you have an earth module fit Check for motor faults to earth That means all motors hoist as well as steer motors,

I know this is long winded but I hope it is helpfull

Regards Titus