Notorious Yellow Wire

Are you positive that there is NOT a Radio Dash switch? Some Winne's used a Dash switch that switched between CHASSIS power for the radio and COACH power for the radio. That switch means that you could use the Radio when camped without draining the chassis battery. Now, since you had blown fuses at the time of changing the batteries, that means at some point you connected the WRONG positive wire. Fuses do not blow when changing batteries unless you short something. You state that there are NO fuses behind the radio. Well after working on Motorhomes for 37 years (still do) I have never seen the OEM remove the inline fuse holders on the back of radios. That means there may be that inline fuse UNLESS you are positive that it is the yellow Winne wires direct to that RED and Yellow from the radio. Now, some OEM's fuse the Radio and some other components AT the battery area or at the battery disconnect area. Double check within a foot or so of the battery area and the Battery disconnect area. If you call Winne, they are usually pretty sharp at where these type fuses may be located as it is a very common complaint. Doug