Many thanks Stam I will try it??

Just something I though of for you to try quick. There should be a plug on the black box "Z" plug. Unplug it and clean/reseat the connector and try.

Good luck.

Hi it doesn't have an ev 100 control card, it's very old, has a fwd contactor, rev contactor and hydraulics contactor, all working, then a pcb and black box where all the terminals are gathered (i assume this is the scr?)and a few fuses. I've removed the battery and connected whilst it's at the side of the truck, the chassis is live with the ignition on? 72v and the motor moves slowly with the wheels raised( no load) and the speed increases with pedal travel. I'm so confused.

If the truck does not show a code you will need a hand set to plug into the ev100 control card in the back of the truck to tell you the code of were to look to try to fix it. if not then it is very difficult to diagnose but not impossible. Good luck.

Are there any codes when you turn on ignition ?