Hi,
So it’s a bit different over here in Aus, we have
Blue: supply line fills trailer tanks and pumps up airbag suspension
Red: brakes, only comes on when you press the foot valve.
Most trucks over here have no air coming out of either hose until you take the park brake off then air will come out the blue supply hose.
The Volvo I had when the park brake was on both air lines had air coming out of them, then when you released the park brake only the blue supply line had air until you pressed the foot valve then the red brake line had air pressure.
So with the man as it is now if the park brake is on NO air comes out of either of the lines.
Hope this clears it up, have checked another MAN over here and it’s exactly the same so it’s obviously setup like this for Australia but I’m hoping to change it.
Cheers,
Nick