KB941-
First off, welcome to iRV2!
Second, you should add a "signature" to your profile. It contains whatever info you want; most people put info about their coach there, so they don't have to type it into each message. Instructions for adding a signature are
here.
Re: Empty relay socket. The Ford F-53 chassis manual should contain a chart of that relay box. You can download a manual
here. Make sure you get the correct one for your coach; your chassis could be a year "older" than your coach.