Thank you for the advise I will try what you have said but the battery is not 100% so will need to sort that first.hope you can assist further if the above dosnt't resolve the problem.The battery is 36V - 18 cells the logic cards shows 36/48 volt options.

Reddog;
Check capacitor's charge up rate and it's charge voltage when the battery is just connected up to the truck. Meter pos on capacitor's positive terminal and the meter negative on the truck's negative terminal in the power distribution panel. You should see no more then 2/3 battery voltage and the charge up rate (RC time constant) will occure. An example would be if the source voltage were 10 volts, the resistance is 10 k ohms and the capcitance is 50 micro F, the RC time constant is 0-5 seconds. After 1/2 second, the capacitor will be charged up to 63% of 10 volts, or 6-3 volts. After another 1/2 second the capcitor will charge up to another 63% of the remaining voltage of 3.7 volts, leaving the capacitor about 86% charged and so on. Not having the truck's battery voltage prevents me from more detailed information.

I thought that may be the case - the appears to be a few burn marks on the buzz link bars on contactors were possibly the logic card has shorted on ? - may be cheaper to retrofit ?

I would guess a bad logic card.

Nissan 50 - D371898

No codes present ? - I believe it was actually imported from American so you may recognise the model ? - it just seems to have no torque ? - until it hits bypass contactor ?

Model AND Serial number would be a help.....plus any codes that are showing up on the display.....