Almost all electrical circuits employed in the operation of the vehicle are protected by fuses, circuit breakers as well as fusible linkages; the main fuse relay is situated in the engine bonnet on the driver's side in front of the battery, and the interior fuse/relay is positioned within the passenger compartment to the left and below the steering column. Different types of fuses are small fuses, medium fuses, and large fuses that are installed in the fuse blocks whereby the small fuses demand a tool and commonly known as fuses pullers made up of pliers or a mini plastic fuse puller. After an electrical component is problematic, one has to observe the fuse first since the element between the terminals which melts whenever a fuse is blown can be easily spotted; the existence of power at the exposed terminal ends is confirmed by using a test light. Faculty from a different rating with the blown fuse jeopardizes circuit protection, so it is vital to use the correct kind of fuse. If a replacement fuse blinks out as soon as it has been placed, then the problem that prompted the blown fuse, common one being a short circuit, should be fixed before another replacement is made. Some of the circuits also have fusible links and these areas include high current areas which can be replaced with links of the same amperes after removing the negative cable of the battery. Circuit breakers guard individual circuits like the power windows or the heated seats, that automatically pop and reset when there is an overload; if it does not, it requires immediate check. A simple form of test is when the CB is slightly withdrawn from the socket, one may probe with a voltmeter to check if battery voltage is available at both ends; often if it is not, then replacement is necessary and some types of circuit breakers may have to be reset physically.