1. Verify the problem. Operate the complete system and list all symptoms as follows: • Check the accuracy and completeness of the complaint. • Learn more that might give a clue to the nature and location of the problem. • Analyze what parts of the system are working. 2. See Section 7 in this manual… Read More »
CAUTION: To prevent damage to the test meter, only use the ohmmeter on circuits when the power is OFF. Power from 12 V systems may damage the meter. The ohmmeter measures resistance (ohms) in a circuit. Ohmmeters use a small battery to supply voltage and current flow through the circuit being tested. Based on Ohm’s… Read More »
An ammeter measures current flow (amperage) in a circuit. Amperes (or amps) are units of electron flow that indicate how many electrons are passing through the circuit. An amp is the unit of measurement for the current flow in the circuit. Ohm’s Law states that the current flow is equal to the circuit voltage divided… Read More »
Use a voltmeter to answer the following questions: • Does the circuit have voltage? • What is the voltage reading? • What is the voltage drop across a load device? To check for voltage to a load device, connect the positive meter lead to the input connection of the device (positive side) and connect the… Read More »
Jumper wires allow a circuit to by-pass a suspected opening or break in a circuit. Use a jumper wire to check for open relay contacts, wire breaks and poor ground connections. Several jumper wires with different tips should be available. If the circuit works correctly with the jumper wire in place, but does not work… Read More »
Test meters come in a variety of models. Any working model will be adequate for simple tests. However, accurate readings are important. Make sure the test meter is of high quality. The Fluke 88 Digital Multimeter (DMM) is recommended because it has very little current and a high impedance (resistance) of 10 megaohms (10 MΩ).… Read More »
Ohm’s Law describes the relationship between current, voltage, and resistance in an electrical circuit. Ohm’s Law also provides the basic formula for calculations. Memorize the formula in the circle. Cover the letter with a finger for the desired formula. For example, I is covered, the formula is I = E ÷ R. If two values… Read More »
Voltage is electrical pressure or force that pushes current through a circuit. The pressure is measured in volts. The symbol V (for example, 12 V) is used in circuit diagrams to denote voltage. The letter E (Electromotive force) is also used for voltage. Voltage can be compared to the pressure necessary to push water through… Read More »
The UV leak detection kit is used with fuel dye to quickly identify leaks. The fuel dye combines with fuel and migrates out at the leak. The ultraviolet lamp illuminates the leaking fuel dye, which appears fluorescent yellow-green in color.
The Crankcase Pressure Test Adapter is used to measure combustion gas flow from the engine breather and may be used with the magnehelic gauge or slack tube manometer. Pressure readings obtained with this adapter must be used as the main source of engine condition. Oil consumption trend data must also be used if the pressure… Read More »