TROUBLESHOOTING INTRODUCTION - CONTINUED
EXPLANATION OF TROUBLESHOOTING TABLE COLUMNS
The columns in troubleshooting tables are defined as follows:
MALFUNCTION. Indicates fault that has occurred in system/equipment.
TEST OR INSPECTION. Indicates test or inspection to be performed to isolate probable cause for fault symptom.
CORRECTIVE ACTION. Indicates procedure to correct the problem.
ELECTRICAL TROUBLESHOOTING--GENERAL INFORMATION
Refer to Electrical General Maintenance Instructions (WP 0213 00) for instructions on using a multim-
eter to check for continuity or shorts and to perform voltage checks. Analyze the symptoms and condi-
tions and use common sense and logic to determine the most likely cause for the problem, then
troubleshoot that circuit first. The more information you have concerning the problem, the easier it will
be to troubleshoot.
Isolate to the subsystem level (in cases where more than one subsystem is involved); next isolate the problem to a single
circuit within the subsystem; then, isolate the problem to the faulty component using the troubleshooting symptom index
Frayed, broken, loose or corroded wiring is a common source of problems in any electrical circuit. Always make visual
inspection before starting detailed troubleshooting. Pay particular attention to contacts to ground and components
with case grounds.
When making continuity checks, make sure the test equipment is isolated from power source or damage to
Most of checks made are voltage checks. Pay particular attention to voltages being checked in procedures. This equip-
ment is a 24 volt system. Instructions prior to the step instruct to disconnect at test point from the potential malfunction-
ing component. Once the check has been made, either repair the component or go to the referenced step. If going to
another step, reconnect connection or do as otherwise instructed, such as install jumper wires using jumper wire kit.
When ready to make the prescribed check, apply power to the circuit (if required). A helper may be required if the
switch or power source is out of reach. Release the power function prior to going on, to avoid damage to equipment.
Refer to the following simplified electrical schematics when performing electrical troubleshooting.