I am. It sure where the alarm is tied in.. maybe try swapping the gauges ? Not sure which tank is which under their .. sounds like you have pressure .. just no gauge. Maybe tap the gauge with a...
If no pressure to the brakes .. they would not release?
were these factory installed ? .
By chance, do you know what they should be set at ?
Any suggestion on brand to use and is it 1/4 npt?