The electrical circuits of the vehicle are protected by fuses, circuit breakers, and fusible links; with the main fuse/relay board in the engine compartment, the interior fuse/relay cases are located behind the left end of the instrument panel and at the right rear corner of the trunk according to the year and model. Small fuses are used in the electrical circuit while medium and large fuses are used in the fuse block, but the all have blade terminal designs; while the medium and large fuses are easily slid out of their positions, small fuses need one to use pliers or a plastic fuse-puller tool. In the case when an electrical component is dead, the check of fuse is a first step; the best way to check whether there is power at the exposed terminal lips of every fuse-use a test light: if there's power at one end but not at the other-the fuse is blown, and, in addition, it may be observed that the element between the terminals is melted. Fuses which have blown should be replaced by the right type as other fuses can appear physically different but should not be used as they will only offer the wrong amount of protection to the electrical circuits, and the amperage value is usually printed on the top part of the fuse body. If a replacement fuse fails immediately, it should not be replaced again until the root problem; whereby usually a short circuit resulting from a damaged or degraded wire is fixed. Also, there are some circuits which are protected by fusible links and these will be in circuits that are not fused or in high current circuits such as the link between alternator and battery; these are made to melt if subjected to high currents and has to be replaced by one of the same rating; more often they will blow again before requiring it to be replaced.