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627333-A 6-1 General Information GENERAL INFORMATION INTRODUCTION The electrical system can be divided into four sections: • Engine; • Operator’s Station; • Electro Hydraulic; • Lighting. Current to electrical systems is provided by a high output alternator with a built-in voltage regulator. These high output alternators are needed because, under certain conditions, very high amperage demands are required. The 12-volt batteries wired parallel have a double negative ground-one to engine frame and one to starter. A double connection is provided to ensure a reliable ground. BASIC TROUBLESHOOTING In troubleshooting electrical circuits the first step is to familiaize yourself with the components, wire routing and connections of the circuit. This can be aided by studying the wiring diagrams in the operator’s or service manual. Each electrical circuit on the machine is isolated to show the wire connections and components used. Most diagrams give a visual approximation of the components to aid in identifying unfamiliar parts. If a module or other electrical component is completely dead, first check the diagram for the correct condition, i.e., ignition switch on, clutches engaged, ect. Check for obvious failure areas like fuses, unhooked connection or broken wires. The ground circuit can also become defective because of a broken wire or poor connection to the frame. Most voltmeter probes are small enough to insert into the back side of the electrical connectors so the supply voltage to a module can be checked without disconnecting it the harness. The greatest percentage of defective connections occur at or near the connectors themselves. Visually check to see that terminals are completely inserted into the housing (no terminal should be exposed above the surface of the connector). This difficult in some connectors below the console and may require removal of the outside cover panel. If the locking tang on the terminal is damaged and will not retain the terminal in the connector, a new terminal from the electrical service kit will need to be installed. Some terminals may just require the locking tang on the terminal be reformed so it will catch the appropriate step in the housing. Immediately behind the connectors is another potential failure area. This is increased if the wires are flexed or sharply kinked. Moving the wires from side to side may produce intermittent contact and locate the general area of failure. Corrosion of the terminals is possible as the machine ages. In some cases simply disconnecting and reconnecting a connector will solve a poor connection problem. Heavy corrosion of terminals may occur since the machine is exposed to or stored with fertilizer of other corrosive products. This will require replacement of the affected terminals to provide reliable connections over a long period of time. In troubleshooting a new machine or an electrical system that has never functioned correctly, check for the possibility that wires in the connector may be crossed or that wires in the connector may be inserted in an incorrect terminal where no continuity between harnesses exists. Wire colors, functions and terminal numbers (on numbered connectors) are listed in the operator’s service manual under Electrical Circuits. Wires that have been exposed to oil or sunlight may require some of the harness covering to be removed to aid in identifying the correct color. |