VALVE GP-PUMP CONTROL 2478846 - Caterpillar

Illustration 1 g03642671
Illustration of the electrical connections fro the Governor Control module.The Automatic Engine Speed Control reduces the engine speed while the machine is inactive. The Automatic Engine Speed Control raises the engine speed from idle to the engine speed dial setting when a machine function is detected.Note: When troubleshooting the electrical components on the machine refer to the electrical schematic in SIS matching your machine.The AEC module monitors two pressure switches and the engine speed dial for increased demand for engine speed.The machine monitor is connected to the AEC module by wire N933-PU. The monitor will display the operating condition of the AEC module. When the AEC module is not operating correctly, there are three inputs that could cause a failure of the module. The AEC module receives input from the speed dial, and two pressure switches. The AEC module is powered by the main battery through a 15 A fuse.The first step in troubleshooting the AEC module is to locate the fuse for the module on the main fuse panel. Refer to the film on the rear of the fuse panel cover to identify the appropriate fuse. Remove the fuse from the panel and use a multimeter that is set to check the resistance across the fuse. If the fuse is open, replace the fuse and operate the machine. If the fuse opens while testing the operation of the machine, wire 130-GN in the wiring harness should be checked for a short circuit. To confirm a short circuit, a temporary replacement wire should be run from the fuse panel to the module. If a short circuit does not occur when using the temporary wire, then an examination of the existing wiring harness is required. Examine the wiring harness for damage, chaffing, or sharp bends that would indicate possible locations for the short circuit. Repair or, if necessary, replace the wiring harness.The AEC module is also dependent on input from pressure switches for determining the demand for increased engine speed. The pressure switches monitoring hydraulic demand are the Implement Pressure switch (Pressure Switch A) and the Travel Pressure switch (Pressure Switch B). Both of these switches are normally in the OPEN position. Disconnect each of the switches from the wiring harness. With the switch disconnected, use a multimeter that is set to resistance, and check the resistance across the switch. If the switch is operating correctly, the multimeter should read OPEN. If the pressure switch is correct, check the wiring harness for the switch. Disconnect the wiring harness at the AEC module and place a jumper wire across pins 2 and 3 of the connector wiring harness. Use a multimeter to check the resistance at the connector for the pressure switch. The resistance measure should be less than 5 ohms. Remove the jumper wire and check the resistance of the circuit again at the connector for the pressure switch. This measurement should reveal that the circuit is open, if the circuit is correct. Repeat this process for Implement