Not sure what you mean by 'everything" works? I'm assuming that since your hooked to your truck when you state "everything works", your saying all 12v items work? Right? If that's the case, when your plugged into 110v, your converter ( assuming you have a converter and not an inverter) should convert 110v to 12v and run the 12v items. Either your inverter is not working, or you have the trailer 12v "breaker" switch turned off. Mine is located on the tongue close to the propane tanks. Without knowing what rv you have, that's about all I can suggest with no further info!
Days camping (2015)----88 days
Days camping (2016) ---110 days
2016 Wildcat MAXX 28RKX (33' TT), 2007 13' Scamp
2015 Ram Laramie Hemi
30 years RV'ing
12 different RV's