APPENDIX F ELECTRICAL AND HYDRAULIC DIAGRAMS

TM 10-3930-638-24&P

APPENDIX F

ELECTRICAL

AND

HYDRAULIC

DIAGRAMS

Section I. INTRODUCTION

F-2. DIAGRAMS

F-1

GENERAL

This appendix contains an electrical diagram and an

The hydraulic diagram is located in figures F-3 and F-4 and

hydraulic diagram. Also included in this appendix is a

the electrical diagram is located in figure F-5. Figure F-3

description of how to use the electrical diagram as an aid

shows the hydraulic oil flow when the various controls are

to troubleshooting (section 11). Section 111 contains the

in the neutral position. Figure F-4 shows the hydraulic oil

diagrams (figures F-3 through F-5).

flow when the controls are activated.

Section II. HOW TO USE ELECTRICAL SCHEMATIC AS AN AID

T O TROUBLESHOOTING

the transmission shift lever not fully engaged in park or

F - 3 . OVERVIEW

neutral.) Try to duplicate the trouble so you can be sure

you're on the right track.

a. Figure F-5. your Electrical Diagram. is designed to

help you understand the electrical circuits associated with

this vehicle. It is generally referred to as a "schematic" and

c. Check troubleshooting index for most likely cause,

uses "symbols" to represent real components. It is not

then identify the circuit that is malfunctioning.

drawn to scale (as in a blueprint) nor does the location of

the symbols represent actual location of components in the

d. Study the electrical schematic to learn which com-

vehicle. It is a simple "picture" of how the circuits and

ponents, harnesses, or wires could contribute to or cause

components are connected together.

the malfunction.

b. To quickly find a malfunction or trouble in the

electrical system and repair it requires an understanding of

NOTE

how the system operates and a method for checking it out.

"Troubleshooting" provides the "method" for check out

Remember, when tracing circuits on the elec-

procedures and your technical manual (Troubleshooting

trical schematic, that you should always start

tables and schematics) provides the "operating principles".

at the positive (+) side of the battery. Current

will flow outward from that point through the

circuits and return to the negative () side of

F-4. TROUBLESHOOTING

the battery by way of ground wires and the

vehicle frame.

Troubleshooting is the systematic (step-by-step) isolation

of a malfunction or trouble to the faulty component,

e. Make necessary tests and checks to isolate circuit or

harness connector/wire. It is a guide that helps develop a

component as outlined in the troubleshooting section of

routine or "way" of finding troubles in any electrical

this technical manual.

system or circuit. As you become more familiar with this

vehicle and gain experience, you will find ways to shorten

f. Make repairs, if you're sure. If not, continue to

these procedures and decrease down time. BEFORE you

isolate the malfunction, or ask for help from your foreman

attempt to make any repairs or checks, do the following:

or supervisor.

a. Find out how the system works under normal condi-

g. After repairs, make sure everything has been re-con-

tions and how to operate it.

netted and tightened.

b. Make sure the malfunction or trouble reported to

h. Make operational checks to verify that the system/

you "really" exists. ("Dead batteries" could end up as a

"failure to start" because of a faulty neutral start switch or

circuit is functioning properly again.

F-1