120H, 12H, 135H, 140H, 143H, 160H and 163H Motor Graders Caterpillar

Many of the troubleshooting procedures in the Testing And Adjusting section require the inspection of electrical connectors. Do the following steps in order to test an electrical connector. These steps can be especially helpful when you are troubleshooting an intermittent problem. If a faulty connection is found, repair the connection. Then return to the original troubleshooting procedures. Check if the original fault is resolved.

Note: Avoid unnecessary disconnecting and connecting of connectors in order to troubleshoot system faults. This practice can cause the connector contacts within the connector to wear out prematurely.

1. Check the hex head screw of the connector. Make sure that the 40-pin connector on the rear of the GSC is aligned and seated properly and that the hex screw is tight. Any unused locations in the 40-pin connector should be plugged in order to keep out dirt, water and contamination.

2. Perform a pull test on each wire. Each connector contact and wire in the various harness connectors should easily withstand 10 pounds of pull. The wire should remain in the connector body. This test checks if the wire in each connector contact was crimped properly. Also, this test checks that the connector contact was inserted into the connector body completely. Perform repair, as needed. When you are replacing connector contacts, use only the 1U-5804 Crimp Tool. Make sure that the connector contact and the tool are matched to the gauge of the wire. Connector contacts should always be crimped onto the wire, never soldered.

   Also do the pull test for the pre-insulated crimp terminals on the terminal strips. Perform repair, as needed. When you replace crimp connections, use the proper crimp tool. Use a terminal that is proper for the gauge of the wire. Spade terminals and ring terminals may be soldered to the wire for an improved electrical connection.

3. Visually inspect the wiring. Look for worn out wires. Check for pinched harnesses or damaged harnesses.

4. Visually inspect connectors and crimp terminals. Verify that connector contacts within the connectors are not corroded or damaged. Verify that the alignment of the contacts and the location of connector contacts are proper. Verify that the two connectors are seated and locked together.

   Check all crimp connections for corrosion. Check all crimp connections for damage. When you are wiggling each wire on a crimp connection, the ends of the bare wires on the open end of the terminal barrel should be tight. Check the tightness of screws on the terminal strips also. Perform repair, as needed.

5. Check individual connector contacts. This is especially important for intermittent problems. When you are using a new connector contact, insert this contact into each of the mating connectors. Check for a snug fit between the mating connectors. Repeat this procedure for the other connector by using a new connector contact of the correct type.