Basic Knowledge Required

Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage (volts), current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram.

The following four-step troubleshooting procedure is recommended:

Check the Problem
Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes.

Read the Electrical Schematic
Study the schematic and read the Circuit Description text to gain an understanding of how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution and Ground Distribution.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty.

Find the fault and repair
Narrow down the possible causes.
^ Check System Fuse(s).
^ Check System Ground(s)
^ For systems with bulb failures, check bulb(s) prior to beginning diagnostic tables.
^ Perform a visual inspection of system components, and accessible related wiring prior to beginning diagnostic tables.

Make the necessary measurements or checks as given in the System Diagnosis.

Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure.

Test the Repair
Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair.