The tanks should have a regulator, that drops the pressure, within the first foot or so of the hose leaving the tanks. To test for gas crack open any connection beyond the regulator, with the tanks on, and see if you smell gas. If no gas there remove the hose from the tank and crack the valve again smell. If gas at the tank and not at beyond the regulator replace the regulator. If nothing from the tank take it to a propane shop for inspection.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles