Look for something like this
I have one near my converter and one near my batteries.
I had to replace the one next to my batteries because of the same problem you are having.
To test If using the multimeter to measure ohms, the reading should match (or nearly match) the one provided when you touched the two leads. If the fuse is blown, it will not read anything at all, or the meter will display O.L. depending on the brand and type of meter you are using.
If using a digital multimeter set to measure continuity, the meter should beep continuously as you hold the leads to the ends of the fuse. That means the circuit is complete. If it does not do so, the fuse is blown. Touch the +&- leads from meter togeather to verify beep before testing
