Troubleshooting procedures are grouped by work packages, containing information you need to fault locate malfunc-
tions on the M915A3 Tractor Truck. A troubleshooting symptom index in WP 0005 00 is provided to aid in locating a mal-
function or symptom and direct you to the appropriate troubleshooting table (work package) containing a listing of
malfunctions, test and inspection procedures, and corrective actions. The corrective action column further directs you to the
required corrective maintenance procedure within this manual by work package number. However, if the required mainte-
nance procedure is beyond Unit Maintenance capabilities, the direction is to notify Direct Support Maintenance.
PRELIMINARY TROUBLESHOOTING PROCEDURES
Fluid leaks are classified as either Class I, Class II or Class III
Seepage of fluid (as indicated by wetness or discoloration) not great enough to form drops.
Leakage of fluid great enough to form drops, but not enough to cause drops to drip from item
Leakage of fluid great enough to form drops that fall from item being checked/inspected.
Before starting any specific troubleshooting procedures, perform the following:
Visually check for ruptured oil hoses or tubes and for Class II or Class III leaks.
Check for mechanical jamming or binding caused by rocks or other foreign matter.
Check fluid levels in subject area and service as required (TM 9-2320-302-10 or WP 0021 00).
Analyze the symptoms and conditions and use common sense and logic to determine the most likely cause for the prob-
lem, then troubleshoot that circuit first. The more information you have concerning the problem, the easier it will be to
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
(WP 0005 00).
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.
When making continuity checks, make sure the test equipment is isolated from power source.
Most of the checks are made by voltage checks. Pay particular attention to the voltages being checked in the procedures.
This equipment has a combination of 12 and 24 volt systems. Instructions prior to the step instruct 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. 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.