Quote Originally Posted by R19 View Post
First remove the fuse from the terminal block. Then set your meter to the ohms setting. Then put the + on one end of the fuse and the - lead on the other end of the fuse. It will not matter which end of the fuse you put the + or - on just as long as they are on the opposite ends where the fuse plugs in. You are looking for continuity (continuous flow) If your fuse is good you will have a small amount of resistance ohms reading. If you have an analog screen and get a reading of 0 (zero) or a digital screen and get a reading of OL (out of limit) your fuse is bad. O Zero or OL out of limit means the path for current can not flow all the way through. This normally means a broken wire or internal part pending what type of fuse your checking. If your meter has a small number reading that means current can flow all the way through the fuse.

If you have a known working fuse that is the exact same size as the fuse in question check the ohms on it. I have seen a bad fuse give a false reading indicating that it is good. If the fuse in question gives an ohms reading of 5 ohms (which would indicate a good fuse)and the known good fuse has a reading of 15 ohms it is possible that the resistance reading was a false reading. If your hands were touching both ends of the fuse and the leads from the meter at the same time the path of flow was actually coming through your body.This does not happen often but it is possible.

Most boat and automotive fuse's do not cost very much. Sometimes I want even bother checking them with a meter because I can change them all for a new fuse and only spend less than $1-2. Which is cheap in my opinion.

If you do decide to check a fuse it is VERY important to remember that the ONLY time you check ohms is when there is no power/voltage/current present. If you try to check ohms on something that has voltage it will fry a cheap meter or blow an internal fuse if you have a more expensive meter.
youre gonna confuse him...a reading of '0',or very close to it is a GOOD fuse...the less resistance the better.