You must have a basic knowledge of the following items before using this section. Without this basic knowledge, you will have difficulties using the diagnostic procedures contained in this section.

If you need a review of basic electrical troubleshooting, see the introduction to How to use Electrical Diagnosis in Wiring Systems. How to use Electrical Diagnosis also contains information on the basic use of circuit testing tools.

You should understand the basic electrical theory. You should also know the meaning of basic electrical concepts and measurement: voltage (volts), current (amperes) and resistance (ohms). You should understand what happens in a circuit with an open or shorted wire. You should be able to read and understand a wiring diagram.

You should be familiar with the high impedance Digital Multimeter (DMM) J 39200 . You should be familiar with the meter controls and how to use them correctly. You should be able to measure voltage, resistance and current. You should also know how to use jumper wires to bypass components in order to test circuits.