what i do is use a 55watt headlamp bulb in place of the fuse,when the circuit is in the fault condition it just lights the bulb,when its lit you can then wiggle wireing looms to look for chafes etc and unplug things to see if the fault condition alters,its good as it saves blowing fuses and lets you see when the issue happens!,its a method ive used for 20+ years as a mechanic,its never failed me yet.