Bill,
If you are referring to your hydraulic leveling system, the 2001 Marquis used a SMC leveling system that has been out of production for 14 years and there are no new modules available. Also I have no heard of anyone who repairs the modules. Your best option is to either find a used module, convert the system to a manual leveling system, or install a HWH air leveling system. BCS (Beaver Coach Sales) sales and installs a conversion kit to convert your system to a manually operated leveling system.
If you are referring to a HWH air leveling system control module, just call them. HWH has excellent product support.
Gerald