Laura,
There are 3 components that control the close out. The switch or switches, the control valve, and the air cylinder. First you need to determine which one if any are malfunctioning. First, you need adequate air pressure for the system to operate. The switch/switches control the air valve that is on the front wall of the LF electrical bay. If the valve changes state when the switch is changed you switch is OK. Next check the air flow at the valve. If it is very restricted, it can be increased with the adjustments on the valve at the air lines.
If you have good pressures and air flow at the valve ports, the problem is probably an air line or the cylinder. Listen for a leak with the system aired up and the engine off before trying to access the cylinder. The operating cylinder is difficult to access on most coaches. If it is not accessible from under the coach, you will have to pull up the carpet above it for access, but cylinder failures are uncommon.
Gerald
