Circuit Functions
The circuit designation system for wiring has been designed to provide complete vehicle logic to the method of naming circuits. This system has been formulated from a whole vehicle point of view.
All circuits in the wiring diagrams use an alpha/numeric code to identify the wire and its function. To identify which circuit code applies to a system, refer to the Circuit Identification Code Chart below.
NOTE:
This chart shows the main circuits only and does not show the secondary codes that may apply to some models.
CIRCUIT IDENTIFICATION CODE CHART
| CIRCUIT CODE | FUNCTION |
|---|---|
| A | BATTERY FEED CIRCUITS (PRIMARY DEDICATED MULTI-SYSTEM FEEDS) (i.e. FUSE LINK FEEDS, FUSE PROTECTION DEVICES, STARTER FEED STARTER RELAY FEED) |
| B | BRAKE CIRCUITS |
| C | CLIMATE CONTROL CIRCUITS (i.e. A/C, HEATER, EBL, HEATED MIRROR) |
| D | DIAGNOSTIC COMMUNICATION CIRCUITS (i.e. Ethernet, CAN, LIN, PCI) |
| E | DIMMING ILLUMINATION CIRCUITS |
| F | FUSED CIRCUITS (SECONDARY FEED FROM PRIMARY FEEDS) |
| G | MONITORING CIRCUITS (i.e. GAGES, CLOCK, WARNING DEVICES) |
| H | **OPEN** |
| I | NOT USED AS A CIRCUIT DESIGNATION |
| J | **OPEN** |
| K | ENGINE LOGIC MODULE CONTROL CIRCUITS |
| L | EXTERIOR LIGHTING CIRCUITS |
| M | INTERIOR LIGHTING CIRCUITS (i.e. DOME/COURTESY/CARGO) |
| N | ESA MODULE ELECTRONIC CIRCUITS |
| O | NOT USED AS A CIRCUIT DESIGNATION |
| P | POWER OPTION CIRCUITS (BATT. FEED) (i.e. SEAT, DOOR LOCKS, MIRROR) |
| Q | POWER OPTION CIRCUITS (IGNITION FEED) (i.e. WINDOWS, SUNROOF) |
| R | PASSIVE RESTRAINT CIRCUITS |
| S | SUSPENSION AND STEERING CIRCUITS |
| T | TRANSMISSION, TRANSAXLE, DIFFERENTIAL, AND TRANSFER CASE CIRCUITS |
| U | **OPEN** |
| V | SPEED CONTROL, AND WIPER/WASHER CIRCUITS |
| W | **OPEN** |
| X | SOUND SYSTEMS (i.e. RADIO, HORN) |
| Y | **OPEN** |
| Z | GROUNDS (NON DEDICATED MULTI-SYSTEM GROUNDS) |