Knight Anglia- LH Agro help!

[Flat 10]

I have a very vexing problem with my Knight and LH4000, when you turn the sprayer on the LH turns off. Also when the sprayer is off the lights are illuminated beneath the individual section controls when switched either on or off, so some kind of feedback? When I'm spraying- ie sprayer on, LH off- individual section controls don't operate- ie switch off. I spent ages looking at it, finally called a professional who checked all wiring, replaced a dodgy fuse holder in the box and took the LH to LH to be tested. It was fine. He then brought a different LH to try on my sprayer mine and that worked fine. We then put my LH back on and that's worked fine for a couple of loads. This morning when went to use the same problem reoccurred. Sprayer hasn't been taken off and nothing has changed. We have both been through wiring with a fine tooth comb but presumably its a wiring fault? I'm tearing my hair out here. Any inspiration gratefully received. @Dennis are you the expert on these? TIA

 

[Midnight plough boy]

Where are you taking power from? Dodgy earth if negative not wired straight to battery?

 

[Flat 10]

Where are you taking power from? Dodgy earth if negative not wired straight to battery?

It’s wired direct thanks

 

[Dennis]

Sounds very strange, I'm really no expert, the Knights ive have we're all very reliable, sorry I can't be any help.

 

[Flat 10]

It was @Derek67 I was thinking of, apologies. @SimpersTradeCounter might well have a bright idea.