WTF is this dash light?

[TheDarkLordChinChin]

Renault 70 14 tractor (1987)
The green light on the right.
It only comes on when I cold start the tractor and switches back off when I rev it. It comes back on if the machine has been running at a high rev for a long time; running a splitter etc.
Any ideas?
Sorry for the crap photo.

 

[uniballer]

Looks like it is supposed to be a battery. Not sure if it is trying to tell you charge state, current flow from the alternator, or what...

 

[TheDarkLordChinChin]

No I have another battery light, it's red like normal and displays a battery.

 

[cookies]

looks like a hydraulic junction block? does it have a pressure sensor on one? fluid check ?

 

[U&A]

looks like a hydraulic junction block? does it have a pressure sensor on one? fluid check ?

I like this answer

Could be as simple as a pressure sensor. But could be a flow issue or a leak


Sent while firmly grasping my redline lubed RAM [emoji231]

 

[TheDarkLordChinChin]

Interesting.
That would make sense if the machine had been running a splitter for a few hours.