5-7. TROUBLESHOOTING SYMPTOMS.
Table 5-1 lists the most common malfunctions found during operation of the trailer. Tests or inspections and
corrective actions should be performed in the order listed. This symptom index lists corrective actions that can be
performed by Direct Support.
5-8. INTRODUCTION TO LOGIC TREE TROUBLESHOOTING.
a. Page Layout. Troubleshooting is divided into symptoms peculiar to a trailer system or component, for
example, air system or inversion valve.
Determine the symptom or condition that indicated a problem or failure. Refer to the System Symptom
Index, Table 5-1.
Go to the referenced page to begin troubleshooting. Open the manual flat so both the right and left pages
are displayed before you. The information on all facing pages is important.
All diagnostic logic and flowcharts are on the left-hand page, with supporting information, warnings,
cautions, notes and test instructions on the right-hand page. Pages are setup so you do not need anymore
than the necessary information, warnings, cautions and notes about a particular question. The experienced
technician generally read just the left-hand page and refer to information on the right-hand page when
needed: all critical information for decision making is on the left-hand page.
How to Begin Troubleshooting.
Identify the symptom or fault.
Follow the diagnostic procedure. Answer question no. 1 on the left-hand page and follow the YES or NO
path to either the remedy or the next page. Helpful information about the problem is also on the left-hand
page. Look on the right-hand page for additional specific instructions.
Observe WARNINGS, CAUTIONS and NOTES. If you see the WARNING symbol on the left-hand
page, look on the right-hand page for the test of the warning. The warning message on the right-hand page
will also have the symbol above it. If you see the CAUTION symbol on the left-hand page, look on the
right-hand page for the text of the caution. The caution message on the right-hand page will also have the
symbol above it. If you see the NOTE symbol on the left-hand page, look on the right-hand page for the
text of the caution. The note message on the right-hand page will also have the symbol above it.
Measurements Required for Troubleshooting.
Connect red test lead to Volt-Ohm input connector and black lead to COM input connector
Set the function/range switch to the desired ohm position. If the magnitude of the resistance is not
known, set the switch to the highest range, then reduce until a satisfactory reading is obtained.