GMC 12004009 Fuse, Auto 20Amps (Yellow)

The electrical circuits of the vehicle are protected by fuses, circuit breakers, and fusible links and the interior fuse / relay block is beneath the instrument panel on the left side of the dashboard while the main fuse/relay is located in the engine compartment. It is always possible to tell which circuit a particular fuse is supposed to protect if one looks at the fuse panel. Miniature link fuses with blade terminal construction are used in the fuse block as the fuses can be easily installed and withdrawn using fingers. When rewiring an electrical component, the first thing to check is the fuse, with a test light, you touch the bare ends of the wire at the exposed terminal tips; if the light goes out on one side but not on the other then you know the fuse is have blown and this can be seen physically. Blown fuses should be replaced by the correct fuses since though physically different fuses of different capacities might be interchangeable but for safety purposes, only the said fuses which should have the right capacity should be fitted to protect each electrical circuit. If a replacement fuse blows as soon as it is put back in place, it should not be replaced again until the root of the problem - which is most frequently a short circuit caused by a broken or aged wire - is fixed.

The best way to check the fuses is with a test light. Check for power at the exposed terminal tips of each fuse. If power is present at one side of the fuse but not the other, the fuse is blown. A blown fuse can also be identified by visually inspecting it.

Each fuse is designed to protect a specific circuit in the vehicle.

If an electrical component fails, checking the fuse first is essential, as a blown fuse can be easily identified through its clear plastic body by visually inspecting the element for damage.

Each fuse is designed to protect a specific circuit.

Small fuses require pliers or a plastic fuse-puller tool for removal.

The electrical circuits of a vehicle are protected by a combination of fuses, circuit breakers, and fusible links.

Bypassing the fuse with metal or foil can cause serious damage to the electrical system.

If a replacement fuse fails immediately, it should not be replaced again until the underlying issue is identified and resolved, typically due to a short circuit in the wiring caused by a broken or deteriorated wire.