Wiring Diagram Circuit Identification

Wiring Diagram Terminal (circuit) Identification
Several wiring circuits in the vehicle's electrical system are identified with a number or letter designation. These circuits are identified the same in all wiring diagrams and are most commonly shown near the top of each page in the fuse/relay panel portion of the wiring diagram. The circuit designations may also be used to identify switch connector terminals (switch circuits). Following are the most common numbered/lettered circuits:

Terminal (circuit):
1 - Ignition coil/ignition distributor low voltage (typically used as an Engine Speed (RPM) signal for the tachometer)

15 - Switched Battery Positive Voltage (B+) from ignition/starter switch

30 - Battery Positive Voltage (B +), hot at all times

31 - Ground (GND)

50 - Starter control; switched B+ from ignition/starter switch

56 - Switched headlight B+ from light switch

58 - Switched parking light, taillight. illumination B+ from light switch

S (SU) - Key In ignition circuit: switched B+ from ignition/starter switch

X - Load reduction circuit; switched B+ from load reduction relay