Fuse Box

Cars usually have one in the engine bay and one inside the cabin. The lid or manual shows which fuse protects which circuit. Some are integrated into control modules. Some fuse boxes contain large main fuses for the alternator and high-current circuits. A spare fuse set and puller are often clipped inside the lid. Corrosion inside the box can create faults that come and go.

Each fuse sits between the power supply and a circuit.

Water entering a fuse box can cause many faults. Always replace a fuse with the same rating.