Using wire instead of fuses under the hood of your 99 Nissan Frontier can have serious consequences and risks. Fuses are designed to protect the electrical system of your vehicle from getting overloaded or short-circuited. When an electrical circuit experiences an excess current flow, the fuse acts as a safety valve and breaks the circuit, preventing damage to the wiring, components, and potential fires.

If you choose to use wire instead of fuses, you are bypassing this important safety feature. Any kind of electrical overload or short circuit can now cause extensive damage to the electrical system of your vehicle. Without fuses, there is nothing to limit the current flow, which can lead to overheating, melting, or even ignition of wires and other components.

Moreover, using wire instead of fuses increases the risk of electrical fires, as the fuses are specifically designed to prevent such situations. An electrical fire could pose a serious threat not only to your vehicle but also to your personal safety.

It is strongly advised to always use the proper fuses specified by the manufacturer for your vehicle. Fuses are generally inexpensive and easily replaceable, so it's better to invest in the correct fuses and ensure the safety of your vehicle and yourself, rather than risking damage, costly repairs, and potentially dangerous situations.