Fuse: Testing and Inspection

When a fuse is blown, there are two probable causes. The two causes can easily be determined by a visual check after removing the fuses.




1. Fuse blown due to over-current.
Prior to replacing the fuse with a new one, check the circuit for a short and the related parts for abnormal conditions. Only after the correction of a short or replacement of abnormal parts should a fuse with the same ampere rating be installed.




2. Fuse blown due to repeated on-off current.
Normally, this type of problem occurs after a fairly long period of use, and is less frequent than #1 above. In this case, you may simply replace with a new fuse of the same capacity.






CAUTION: A blade type fuse is identified by the numbered value in amperes. If the fuse is blown, be sure to replace a fuse with the same ampere rating. If a fuse of higher capacity than specified is used, parts may be damaged and a danger of fire exists. To remove or insert a fuse, use the fuse puller in the fuse box.




A blade type fuse has test taps provided to allow checking the fuse itself without removing it from the fuse block. The fuse is good if the test lamp lights up when one lead is connected to the test taps (one at a time) and the other lead is grounded. (Turn the ignition switch so that the fuse circuit becomes operative.)