'98 Chieftain engine doesn't charge house batteries

Look for the battery control center. There should be a charge relay there. Look for make and model of charge relay.
Look adjacent to the batteries. Some have the batteries under the entry step. A metal dead front hides the battery disconnects and the charge relay.
If you have an auxilary start button on the dash, the same relay in many are the same. Operate it and have helper listen for the relay.