This is a schematic diagram of auto fuse monitor circuit. This circuit is very useful for automobile application, checking a live fuse without wasting any electrical power if the fuse is working fine. This circuit can check the fuse  without removing the fuse from the working circuit. When the fuse is being tested, this fuse tester  is connected across it. If the either LED glows, the Fuse is blown. This testing can be done only if the circuit is live (powered). Here is the schematic diagram of the fuse monitor circuit:

Auto Fuse Monitor circuit schematic