RV Repair: Onan generator not powering RV, amp plug, panel switch

Question
Hi.  I own a 1979 Dodge Tioga which when plugged into 12VAC source powers the outlets inside the RV. Problem is when I disconnect it and run the Onan 4.0 generator, none of the outlets work and according to the battery LED light in the control panel, is not charging the battery. I suspect it is not even getting power to the control box itself. I checked power from the generator at the junction box and is OK, and both fuses OK.  Does the control panel switch the RV from being plugged into 12VAC to running off the generator, and what actually does the generator power when running? I obviously know little about RV's because I just bought this one, recently. Thank you so much for your help!  

Answer
They usually have a transfer switch(ATS). These are setup between the generator and the breaker box. It is  a large box with 2 wires on one side and 1 wire on the other(most of the time). It will have several solenoids inside for switching. Some of the older MH's did not have the switch and would plug straight in to the generator. Check your generator and see if it has a receptacle for your 30 amp plug.