Constant electrical whine (coolant sensor i think)

[rosss]

Hello...
I've got a more or less constant electrical whine in the cab as I drive... it's sometimes not there - but always after the engine has warmed up it comes on.
I got a new battery put in about 6 months ago and it almost completely disappeared but now it's slowly come back.
It responds to the van's movement - so if i apply the brakes when i'm going quite fast it dips in volume and tone.
It's driving me nuts.
I'm pretty sure it's coming from under the dash - under the steering wheel - and i think it's the coolant sensor alarm that must be a bit faulty or something.
It's not the actual coolant alarms sound though as that is much louder. (there's a test button.)
There's a widget on the dash next to the coolant alarm that i don't know what it is... the coolant alarm is the little red light with the button under it. then to it's left - fitted into the light grey part of the dash is another little light thing, sticking out. Anyone know what that is?
I've taken a couple pictures around the back. I can see that the white wiring is the coolant alarm - and the red wiring is the other thing that's been added. But i'm not really sure where to go from here. Seems really hard to access any of it to see if there's a faulty connection or anything.
Anybody has any pointers that'd be very much appreciated

image links:
https://ibb.co/89xVbt7
https://ibb.co/zQzZS31
https://ibb.co/zPtgtrJ

Thanks

[haydn callow]

That’s not one of our alarms.
Just saying !

[Bob]

Possibly the switch left of the lca is for the rear fog light.

Try turning on the headlights then pull it and see.

As for the lca, could you just disconnect it somewhere and see if the noise goes away?

[rosss]

That’s not one of our alarms.
Just saying !

haha....
i wanted to unhook the alarm and see if the sound stopped but it seemed really tricky to get behind the fusebox down there - and then i thought that even if i could get to it i wouldn't know how to do it... so maybe need to pop it into a garage,,,
thanks

[g8dhe]

Just a thought have you got a radio or audio system turned on at all (anywhere in the van) ? Sometimes there can be "alternator whine" emitting from anything with speakers in connected to the vans 12 volt system, try making sure all systems are really OFF (disconnect, remove faceplates etc) and see if it has any effects on the noise ?