HARNESS AS-CHASSIS 1808701 - Caterpillar

Service Procedure F
Diode Test
Use the 6V7070 or the 6V7800 Multimeter for this test, and turn the multimeter dial to the Diode position, Disconnect the diode from its circuit.1. Connect the positive probe of the multimeter to one end of the diode and the negative probe to the other end of the diode. Make a note of the multimeter reading.2. Now reverse the multimeter connections on the diode. Make a note of these readings.If the reading was high in one test and low in the other test, the diode is good. If the readings were the same in both tests (either high or low), the diode is bad and needs to be replaced.Service Procedure G
Pressure Switch Test
Use the 1U5470 Engine Pressure Group and a continuity check for this test. If an access hole to the same pressure is not close or not available, remove the switch and install a tee at this location. Install the pressure switch in one side of the tee and connect the correct pressure gauge (from the 1U5470 Engine Pressure Group) to the other side of the tee. This test can also be performed on bench by using air pressure if the correct fittings are available.With the wires disconnected from the pressure switch, check continuity of the switch terminals with the engine stopped and also with the engine running at the correct speed. Make a note of the pressure gauge reading when the continuity of the switch terminals changes. Compare this pressure reading with the correct specifications for the switch. If the pressure switch has 3 terminals, first check the continuity of both the N.O. and N.C. terminals to the common terminal with the engine stopped. Now use the N.O. terminal (had no continuity when the engine was stopped) for the test with the engine running. This will make sure that, when the switch breaks contact across the N.C. terminal, it moves all the way to close across the N.O. set of contacts at the other terminal.Service Procedure H
Slave Relay Test
Remove the relay(s) from the junction box. Connect the negative lead of a 24 volt source to terminal 5 of the relay and connect the positive lead to terminal 1. Use a voltmeter to check the relay as follows:1. Touch the negative probe of the voltmeter to terminal 5 and the positive probe to terminal 2. Voltage reading should be 24 volts.2. With negative probe of voltmeter still at terminal 5, touch positive probe to terminal 3. Voltage reading should be zero.Now put a jumper across terminal 1 and terminal 4.3. Touch negative probe of voltmeter to terminal 5 and touch the positive probe to terminal 2. Voltage reading should be zero.4. With negative probe still at terminal 5, touch positive probe to terminal 3. Voltage reading should be 24 volts.If any of the readings from the above tests are incorrect or opposite from those shown, the relay is bad and should be replaced.Service Procedure J
Water Temperature Switch
Use the 8T0470 Thermistor Thermometer Group and the