The current owners of old used RV's often don't have the original owners manual or manuals for the house box appliances. Owners manuals are usually generic and don't include detailed electrical schematics, servicing or troubleshooting info. Try to buy a Chilton's or other maintenance/service manual for the equivalent Dodge van, available from auto supply stores or online sources. There are helpful generic how to manuals for operation and maintenance of RV available from RV supply stores. Try to learn about servicing Dodge carbs, ballast resistors, the large electrical connector that goes through the firewall, fusible links, and other quirks. Look for the Dodge RV owners thread on this forum. You have a new hobby!!