Five-Step Trouble Shooting

1. Verify the complaint.
^ Perform System Performance Test, if section has one outlined at the beginning of section.
^ Learn more about the nature and location of the problem. Use the general description to learn how the circuit operates, when the circuit should operate, and how the components interact to make the circuit complete.
^ Analyze what parts of the system are working.
^ Do not fix only part of the problem.
^ Do not begin disassembly or testing until you have narrowed down the possible causes.
2. Analyze the electrical schematic and consult the flowcharts for the system being tested.
^ Look at the electrical schematic for the problem circuit. Determine how the circuit is supposed to work and look for minifuses, maxifuses, circuit breakers, wires, and grounds that are shared with other systems or components. See if a shared wire is at fault by checking other components fed by the wire. If several circuits fail at the same time, check for a common voltage or ground connection. If part of a circuit fails, check the connections between the part that works and the part that does not work.
^ Follow the flowcharts to find the possible cause(s) of the problem.
^ Based on the symptoms and your understanding of the circuit operation, identify one or more possible causes of the problem.
^ Refer to component location diagram for the system to help locate component and/or connector while diagnosing.
3. Isolate the problem by testing the circuit. Use diagnostic service probes as needed on .35, .50, and .80 mm square wires.
^ Perform circuit tests to check the diagnosis made in step two. You can either test for the most likely cause of failure first, or perform tests which are most easily and quickly done.
^ Generally, fuses and grounds are easiest to check.
4. Fix the problem.
^ Once problem is identified, make repair.
^ Make sure to use the proper tools and safe methods.
5. Make sure the circuit works.
^ Operate all components in the repaired circuit in all modes of operation and verify that the repair has removed all symptoms.
^ Make sure no new problems have come up and that the original problem has been fixed.