Some Inverters are also converters
#1 Suggestion is the "Salesman's Switch" May be marked AUX or may be marked Use/Store
#2 is a main fuse or circuit breaker.
How to find problem: Tools needed: A test light. this is a device that you get at Auto stuff places (Auto zone, Discount Auto Napa Auto dept at super store)
Looks like an ice pick with a light in the handle and a wire
Clip wire to unpainted metal part and touch positive battery terminal. Bright good. all else bad
Now move on out the positive lead till you find a terminal. Touch Bright good
If you have to move the ground clip re-test last good point to make sure you have a good ground
Problem exists between bright and dark
