The fuse is the most common method of protecting an automotive wiring circuit. Whenever there is an excessive amount of current flowing through a circuit the fusible element will melt and create an open or incomplete circuit. Fuses are a one time protection device and must be replaced each time the circuit is overloaded. To determine if a fuse is open, remove the suspected fuse and examine the element in the fuse for an open (2). If not broken (1), also check for continuity using a Digital Multimeter. If the element is open or continuity is suspect, replace the fuse with one of equal current rating.
Current Rating Amperes  | Color  | 
|---|---|
Auto Fuses, Mini Fuses  | |
2  | Gray  | 
3  | Violet  | 
5  | Tan  | 
7.5  | Brown  | 
10  | Red  | 
15  | Blue  | 
20  | Yellow  | 
25  | White or Natural  | 
30  | Green  | 
Maxi Fuses  | |
20  | Yellow  | 
30  | Light Green  | 
40  | Orange or Amber  | 
60  | Blue  | 
50  | Red  |