Amazone zam control

[Chimera]

Good evening, hoping to glean some advice/answers from the esteemed machinery collective. We have an amazone ZAM 3001 control with auto forward speed rate control. It opens up as speed increases, but then sticks at the fastest speed setting, and doesn't shut down as you slow down. Anybody had anything similar? I assume the control box needs to be sent somewhere.

 

[Barley man]

I had the same problem an a amazone sprayer @ 18 month old , when the problem was found the control box had been spiked and altered all the settings caused by a fault in wire loom , cure was a new wiring loom and new control box . But check your speed sensor and the multi plug that plugs into the control box and make sure all the pins are clean and not bent out of line .