Harness Wire Identification
Caterpillar identifies all wires with eleven solid colors. The circuit number is stamped on the wire at a 25 mm (1 inch) spacing. Table 1 lists the wire colors and the color codes.
| Color Codes for the Harness Wire | |||
|---|---|---|---|
| Color Code | Color | Color Code | Color |
| BK | Black | GN | Green |
| BR | Brown | BU | Blue |
| RD | Red | PU | Purple |
| OR | Orange | GY | Gray |
| YL | Yellow | WH | White |
| PK | Pink | ||
For example, a wire identification of A701-GY on the schematic would signify a gray wire with the circuit number A701. A701-GY identifies the power circuit for the No. 1 Injector solenoid.
Another wire identification on the schematic is the size of the wire. The size of the wire will follow the wire color. Wire size or gauge is referred to as AWG (Americal Wire Gauge). AWG is a description of the diameter of the wire.
For example, a code of 150-OR-14 on the schematic would indicate that the orange wire in circuit 150 is a 14 AWG wire.
If the gauge of the wire is not listed, the wire is 16 AWG.
Conversion of AWG Numbers to Metric Measurements
Table 2 shows the various AWG numbers that are used. The metric equivalents for the diameter of the AWG numbers are also shown.
| Metric Equivalents for AWG Numbers | |||
|---|---|---|---|
| AWG Number | Diameter (mm) | AWG Number | Diameter (mm) |
| 20 | 0.8 | 14 | 1.6 |
| 18 | 1.0 | 12 | 2.0 |
| 16 | 1.3 | 4 | 3.2 |
Welding on Electronically Controlled Engines
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The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere. |
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Proper welding procedures are necessary in order to avoid damage to the engine's ECM, sensors, and associated components. When possible, remove the component that requires welding from the engine. When welding on a Caterpillar Electronic Engine and removal of the component is not possible, the following procedure must be followed. This procedure is considered to be very safe. This procedure will also provide the minimum amount of risk to the electronic components.
- Stop the engine. Turn the keyswitch to the OFF position.
- Turn off the fuel supply to the engine.
- Disconnect the negative battery cable from the battery. If a battery disconnect switch is installed, open the switch.
- Protect the wiring harness from welding debris and from spatter.
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| Illustration 1 | g01125796 |
Proper placement of the welder ground clamp. | |
| NOTICE |
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Do not ground the welder to electrical components such as the ECM or sensors. Improper grounding can cause damage to the drive train bearings, hydraulic components, electrical components, and other components. Clamp the ground cable from the welder to the component that will be welded. Place the clamp as close as possible to the weld. This will help reduce the possibility of damage. |
- Use standard welding methods to weld the materials.