Mini fuses are protective circuit breakers between a direct current (DC) power supply and the electrical circuits in a car or boat. The fuse panel holds multiple fuses in the same location with numbers next to each to identify which system or appliance they connect. The mini fuses are the first things to inspect anytime electrical items stop working. Replace mini fuses that burn out to keep your DC components in working condition.
Check the fuse panel map to find the corresponding number for the fuse or fuses connected to the malfunctioning system. Automobile owners manuals contain fuse maps.
Pull out all fuses associated with the system to see if they are blown. Use a fuse puller wrench to grip the mini fuse, or attempt to extract fuses by hand. Use a pair of needle nose pliers to grip a fuse that is firmly stuck in the port.
Look through the translucent window in the middle of the fuse between the plug prongs. Check for burn scores in the window, or breakage in the wire. Replace mini fuses with broken wires or burnt windows.
Check the number printed on the back end of the mini fuse. This marks the number of amps the fuse is rated to handle. Mini fuses are generally colour coded for easy replacement, but there are more than one set of colours used, so check the amps listed on replacement fuses. Use a replacement fuse rated to carry the same number of amps as the original.
Plug the replacement fuse into the port that held the blown fuse. Push the back end of the fuse firmly to plug the fuse in properly. The back end should be at the same level as the rest of the mini fuses in the panel. Test the electrical system to find if the replacement fuse has restored function.