Originally Posted by Scottsville Travelers
Thanks for your help. It was to the left of the heater outlet. There was a 30 amp fuse blown. I will replace it and see what happens.
You're welcome. A fuse that big sounds like a converter reverse polarity fuse. It should be labeled in your distribution panel as to what it is (but maybe not). If you touch the wires backwards on your battery, this fuse(s) blows in order to protect your converter from damage.
The converter is what takes 120 volt AC power and 'converts' it to 12 volt DC power..... to provide power to the 12 volt things in your RV, like lights, fans, furnace, thermostats, slides, electric stabilizers, pumps, etc. The converter also is a battery charger to recharge the battery.
If you are not connected to a form of 120 volt AC power, then the aforementioned items run off the battery, and thus will run the battery down. The battery allows you to camp at places where you may not have 120 volt AC power. Without 120 volt AC power, you can use everything in your RV, except the air-conditioner, microwave, or anything that plugs into an electric outlet.
Once you blow the reverse polarity fuse(s), then a lot of the 12 volt DC stuff will run off the battery (usually even if connected in reverse). However, the battery will deplete since the converter cannot recharge it (fuse blown)....then ALL of the 12 volt items will cease to function......until you recharge the battery....... which the converter cannot do since it has it's protective reverse polarity fuse(s) blown.
It's extremely easy (and very common) to connect the battery(s) in reverse...which is why the necessity for the reverse polarity fuse(s).
It also doesn't help that RV's can use different wiring colors than many people are familiar with....which leads to the connecting of the wires backwards.
They can be wired similar to a house, black is hot +, and the negative is white. Many people hook the battery backwards when they have a black and white wire. The black is usually the positive hot +.
Or they can be wired like you are used to in an automobile, where the red is hot +.
Here is a pic of a correctly connected single RV battery. The black and/or red go to the positive + terminal, and the white connects to the negative - terminal.