All the electrical circuits in your Honda Civic have fuses to protect them from a short circuit or overload. These fuses are located in three fuse boxes. Visit https://automobilediagram.com/honda-civic-2004-owners-manual/ for a copy of the owners manual.
Interior Fuse Box
The vehicle’s fuses are located in two fuse boxes. The interior fuse box is located underneath the steering column. To open it, turn the knobs as shown.
Fuse Box Under-hood
The under-hood fuse box is located on the passenger’s side next to the battery.
If something electrical in your Honda Civic stops working, check for a blown fuse first. Determine from the chart on pages and or the diagram on the fuse box lid, which fuses control that device. Check those fuses first, but check all the fuses before deciding that a blown fuse is the cause. Replace any blown fuses, and check if the device works.