Wiring on compressor line, need help

[Geo.Lander]

Hey guys!
Doing some system cataloging so I can get the workshop #todo list ready for when we ship the truck to the UK, I came across this wiring on the compressor hose and didn't manage to trace it back anywhere, anyone have ideas? Looks like it has a spark plug fitting on it...

 

[Sitec]

If its the black plastic looking button on the main steel line just above the fuel filter, it is likely the engine crank button. You can crank the engine to start it with the cab tipped. Mine has the same button but on the opposite side...

 

[Neil]

Mine has exactly the same button. It starts your engine when the cab is tipped.

The problem when you use it is the stopping it .

Neil

 

[Geo.Lander]

Mine has exactly the same button. It starts your engine when the cab is tipped.

The problem when you use it is the stopping it .

Neil

Right! I didn't even notice it was a button!

I left it running then tilted the cab to find a failed gasket. managed to stop it by loosening the throttle cable a wee bit (my exhaust / engine brake button is broken for now, as well as my lockers and low range, must be an airline cut somewhere).

 

[Neil]

must be an airline cut somewhere)

If the airline was cut I am pretty sure you would hear it .
All of those devices that don't work are on the same Auxiliiary circuit, usually the last one to be pressurised.
If you can't findca physical air leak then I would be looking at the 4 way protection valve. It will be near your tanks and will look a bit like the photo below. Each turret has a very sensitive spring valve. Each turret is a different circuit. You could tap each one when the pressure is up to see if it frees it up . They do fail.
This is where I would start to look

Neil

 

[Geo.Lander]

If the airline was cut I am pretty sure you would hear it .
All of those devices that don't work are on the same Auxiliiary circuit, usually the last one to be pressurised.
If you can't findca physical air leak then I would be looking at the 4 way protection valve. It will be near your tanks and will look a bit like the photo below. Each turret has a very sensitive spring valve. Each turret is a different circuit. You could tap each one when the pressure is up to see if it frees it up . They do fail.
This is where I would start to look

Neil

Thanks Neil!

 

[Alloy]

Right! I didn't even notice it was a button!

I left it running then tilted the cab to find a failed gasket. managed to stop it by loosening the throttle cable a wee bit (my exhaust / engine brake button is broken for now, as well as my lockers and low range, must be an airline cut somewhere).

There's apps and detection tools for ultrasonic sound that air leaks make.