All grounds, in-line connectors, pass-through grommets, and splices have identifying numbers that corresponds to where they are located in the vehicle. The following table explains the numbering system.
Callout Numbers  | Zone Description  | 
|---|---|
100-199  | Engine compartment (All forward of the dash panel) Note: 001-099 are additional for the engine compartment (Only to be used if all 100-199 items are used)  | 
200-299  | Within the instrument panel area  | 
300-399  | Passenger compartment /truck bed (From instrument panel to the rear wheelhouse)  | 
400-499  | Truck bed (From the instrument panel to the rear wheelhouse)  | 
500-599  | Within the left front door  | 
600-699  | Within the right front door  | 
700-799  | Within the left rear door  | 
800-899  | Within the right rear door  | 
900-999  | Within the endgate door  |