When a light, socket or accessory stops working, a blown fuse is often the cause. The fuse box diagram tells you which fuse protects which circuit. Here is how to read one.
Find the right fuse box
Most cars have more than one fuse box. One is usually in the engine bay, and another is inside the cabin, often under or beside the dashboard or in a side kick panel. Your owner’s manual shows where each one is.
Read the diagram
The diagram is often printed inside the fuse box lid, and always in the owner’s manual. It shows a numbered position for each fuse, what that fuse protects, and its amp rating. Find the circuit that has stopped working, note its number and rating, then find that position in the box.
Blade fuse colors
Standard and mini blade fuses use the same color for the same amp rating, which makes them easy to check at a glance.
| Color | Rating |
|---|---|
| Tan | 5 amp |
| Brown | 7.5 amp |
| Red | 10 amp |
| Blue | 15 amp |
| Yellow | 20 amp |
| Clear | 25 amp |
| Green | 30 amp |
Check and replace a fuse
- Turn the ignition and the affected accessory off.
- Pull the fuse with the puller tool usually clipped inside the box.
- Look through the plastic. A broken metal strip means the fuse has blown.
- Fit a new fuse of exactly the same amp rating.
Never fit a fuse with a higher rating than the diagram shows. If a new fuse blows straight away, there is a fault in that circuit that needs tracing, and the wiring diagrams in your workshop manual show how.