Harness Wire Identification
Caterpillar identifies different wires with eleven different solid colors. Table 1 lists the color codes of the wiring.
| Color Codes for Wiring | |
| Code | Color |
| BK | Black |
| BR | Brown |
| BU | Blue |
| GN | Green |
| GY | Gray |
| OR | Orange |
| PK | Pink |
| PU | Purple |
| RD | Red |
| WH | White |
| YL | Yellow |
In addition to the color, the entire length of each wire is stamped with a specific circuit number that is repeated on every 25 mm (1 inch) of the wire. The actual wires are identified on the schematic.
For example, a code of J011-RD on the schematic identifies a red wire that is stamped with the circuit number J011. This particular wire is the engine harness wire for the primary signal of the transformer in the number one cylinder. For all Caterpillar engine harnesses with electronic ignition systems, the code of J011-RD identifies the wire for the primary signal of the transformer in the number one cylinder.
The schematic also identifies the size of the wire. The size or gauge of the wire is called the American Wire Gauge (AWG). Unless the schematic specifies a different size, you may assume that the wire is 16 AWG.
Terminal Boxes
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| Illustration 1 | g01077820 |
There are two terminal boxes on the engine. (1) Terminal box for the master Electronic Control Module (ECM) (2) Terminal box for the slave ECM | |
Terminal Box for the Master ECM
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| Illustration 2 | g01077868 |
The connectors on the terminal box for the master ECM connect the master ECM to various engine controls, sensors, actuators, etc. (3) Emergency stop button (4) Connector J6/P6 for the harness to the detonation sensors on the left side of the engine (5) J9 service tool connector for the Caterpillar Electronic Technician (ET) (6) Connectors J8/P8 for the harness from the engine (7) Connectors J7/P7 for the harness from the engine (8) Ignition harness for the cylinders on the left side of the engine (9) Connectors J10/P10 for the harness to the Machine Information Display System (MIDS) | |
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| Illustration 3 | g01085132 |
Components inside the terminal box for the master ECM (10) Master ECM (11) Ground strap (12) J2/P2 connectors (13) J1/P1 connectors (14) J5 connector for wiring to the customer's connections (15) P50 connector for calibration of the speed/timing sensor (16) J13/P13 connector for the termination resistor for the CAN data link (17) Relay for activation of the throttle actuator (18) Relay for activation of the compressor bypass valve's actuator | |
Terminal Box for the Slave ECM
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| Illustration 4 | g01078052 |
Connectors on the terminal box for the slave ECM (17) Connectors J12/P12 for the wiring harness to the detonation sensors on the right side of the engine (18) Ignition harness for the cylinders on the right side of the engine (19) Connectors J11/P11 for the wiring harness to the terminal box for the master ECM | |
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| Illustration 5 | g01078056 |
Components inside the terminal box for the slave ECM (20) Slave ECM (21) Ground strap (22) J4/P4 connectors (23) J3/P3 connectors | |
Optional Control Panel
The engine may be equipped with a control panel. Refer to Systems Operation, "Engine Control Panel" for the descriptions of the panel's controls and displays.
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| Illustration 6 | g01096133 |
Optional control panel (1) Display for the Machine Information Display System (MIDS) (2) Keypad for the MIDS (3) "EMERGENCY STOP" button (4) "ENGINE ON" indicator (5) "ACTIVE ALARM" indicator (6) "ENGINE FAILURE" indicator (7) "MANUAL PRELUBE" switch and "PRELUBE ACTIVE" indicator (8) Engine control switch (9) "DESIRED SPEED" potentiometer (10) Service tool connector | |
Power Distribution Box
The power distribution box is located on the left side of the engine. The engine's electrical power supply and the alternator (if equipped) are connected to lugs that are inside the box. The box also contains five fuses. Refer to Illustration 7.
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| Illustration 7 | g01096525 |
Left side view (1) Power distribution box (2) 20 amp fuse for the throttle actuator (3) 15 amp fuse for the actuator for the compressor bypass (4) 15 amp fuse for the electronic control modules, the MIDS, and the service tool (5) 6 amp fuse for the fuel metering valve (6) 6 amp fuse for the keyswitch and the integrated temperature sensing module (7) Connection for the +Battery from the engine's power supply (8) Connection for the -Battery to the throttle actuator (9) Connection for the -Battery to the actuator for the compressor bypass (10) Connection for the -Battery to the fuel metering valve (11) Connection for the -Battery to the electronic control modules, the MIDS, and the service tool (12) Connection for the -Battery to the electronic control modules, the MIDS, and the service tool (13) Connection for the -Battery from the engine's power supply | |