Do not remove, install, connect, or disconnect any electrical component unless
vehicle MASTER disconnect switch is OFF. To do so could result in injury to
If checking for continuity, MASTER disconnect switch must be OFF to prevent
damage to equipment.
If checking for +24 VDC, MASTER disconnect switch must be ON.
Before starting detail troubleshooting procedures, review the wiring diagram to thoroughly
familiarize yourself with the circuit(s) involved. Refer to SEE wiring diagram, NSN 7610-01-475-7996.
Analyze the symptoms and conditions and use common sense and logic to determine the most likely
cause of 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 detail troubleshooting. Observe, in particular,
contacts to ground. Components with case grounds are especially troublesome.
Most of the checks are made by voltage checks. Instructions prior to the step may instruct you
to disconnect at test point from the potential malfunctioning component. Once the check has been
made, either repair the component or go to the referenced step. 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.
When making continuity checks, make sure the test equipment is isolated from the power