The electrical systems of the vehicle are protected by fuses, circuit breakers, and fusible links with current cars having several fuse and relay boxes incorporated. In a car, there is always any specific fuse; every fuse is located at different places, irrespective of the fact that the main fuse/relay panel is placed in the engine compartment; however, every fuse safeguards a particular circuit that is named on the fuse panel legend. The fuse box has become complicated with more than one site for fuses and relays and perhaps non-servicing micro-processors and internal connections, therefore if they become a problem, it is all or nothing. For the cars produced in 2005 and earlier, the location of the passenger compartment fuse box is at the driver's side of the car. There is the left kick panel fuse box, and the engine compartment fuse box is situated behind the battery, but under the hood. For 2006 and next years the passenger compartment fuse box is located in the driver's side knee bolster panel, while extra modules are situated in the front and rear part of the automobile. Fuses vary in size and kind which located at fuse blocks, and when an electrical component fails, one has to look at the fuses because they may be the problem using a test light to identify whether a fuse has gone off. Fuses that have been blown should be replaced with the correct types; this is because wrong rating circuits affect the protection of the circuits. If, for instance, replacement of a fuse leads to its failure as soon as again, then the problem should be resolved probably by constricting a short circuit before trying another switch again. Some circuits have fusible links that are used in high current; an indication is a bulge in the cable or cartridge type links in the engine compartment and fuse and relay box and these can be replaced by units of the same amperage while the negative battery terminal is disconnected.