Most older units did not charge the chassis battery when the coach was hooked to 110 power . So the wiring in question may be an add on.
The voltage you are getting would be full convertor/charger output, so the wiring has to be insulated , removed ; or hooked up. You have to check the wires back to their source before you hook up, because if they go direct to the coach batteries, you run the risk of draining the chassis batteries and causing a no start condition , if the coach batteries run down, then the chassis battery goes down too. If there is a lenght of wire involved and there is no fuse, then it is a fire hazard, remove it completely and set your chassis battery up with a 110v battery tender, to charge it when your on 110 power.