1987 MITSUBISHI MONTERO wheel

8-208 AUTO
ATIC FREE-WHEELING HUB INDICAUOR SYSTEM - General Information
GENERAL INFORMATION ’ N08RAAA
This system is composed of the automatic free-wheeling hub indicator light, the vehicle-speed sensor (reed
type switch), the automaic free-wheeling hub itidicator control unit, and the pulse generator.
The pulse
generator is located at the rear part of the front output shaft of the transfer; the vehicle-speed
sensor is incorporated within the combination meter.
Based upon the output signals from the pulse generator and from the vehicle-speed sensor (reed type
switch), the automatic free-wheeling hub indicator control unit judges whether the automatic free-wheeling
hub is in the locked condition or the free condition.
When it is in the locked condition, the indicatok light
illuminates; when it is in the free condition, the
indicator light does not illuminate.
This is, therefore, a system which makes it easy to see, from the driver’s seat, whether the automatic free-
wheeling hub is in the locked condition or the free condition.
I j
21 1
Automatic free-wheeling hub
hub indicator
16W1506 16W1567
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AUTOMATIC FREE-WHEELING HUB INDICATOR SYSTEM - General Information 8-209
OPERATIONAL CHARACTERISTICS OF THE SYSTEM
Time-----w
16W1548 Indication by automatic free-wheeling hub indicator light
No illumination of the indicator light when the ignition key is turned from OFF to ON,
regardless of the condition of the automatic free-wheeling hub.
The indicator light illuminates when the automatic free-wheeling hub is locked and pulse
signals are output from the pulse generator, and when, in addition, the vehicle-speed sensor
detects a vehicle speed of approximately 2.5 mph (4 km/h) or higher.
The locked condition is entered in the memory even if the vehicle is stopped (with ignition
key still at ON) while the automatic free-wheeling hub is in the locked condition, and the
indicator light illumination continues.
After the automatic free-wheeling hub is changed from the locked condition to the free
condition (the pulse signals from the pulse generator cease), the indicator light remains
illuminated until the vehicle-speed sensor detects a vehicle speed of approximately 2.5 mph
(4 km/h) or higher. Symbols used in
above diagram
A
B
C
D
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8-210 AUTOMATIC FREE-WHEELING HUB INDICATOR SYSTEM - General Information
EXPLANATION OF INDICATOR OPERATION
.
1.
2. Automatic free-wheeling hub in locked condition
The
output of the pulse generator is input to $ertninal 4 of the control unit, and the output signals from
the vehicle-speed sensor are input
to termi#al 3 of the control unit.
Only when there are pulse signals from the pulse generator, and when, moreover, the vehicle-speed
signals indicate a vehicle speed of approximatkly 2.5 mph (4 km/h) or highter does the control unit judge
that the automatic free-wheeling hub is the locked condition at the lock-discrimination circuit of the
control unit, and therefore the set signal (locked condition) is output.
This signal is entered into the memory circuit, thus causing the indicator light to illuminate.
Pulse generator Speed sensor
(Reed switch)
Pulse-detection circuit / I I
Memory circuit rp*
I
Automatic free-wheeling hub Lock-discrimin&ion circuit
indicator control unit 16W1535 Ignition switch
‘use No. 3 n
J 2
I_
Power-supply circuit
Vehicle-speed
detection circuit 1
Sub fusible link 1
Main fusible link 1
)
1
Battery
When vehicle is stopped (with ignition key still at ON) with automatic free-wheeling hub locked
Signals are not output from the pulse generator and the vehicle-speed sensor when the vehicle is
stopped.
However, because the set signal (locked condition) is entered into the memory circuit, the indicator light
shows the condition in effect when the vehicle was traveling.
Pulse generator Speed sense
Pulse-detecti: ci~uit~~I~ #
Lock-discrimination circuit
Memory circuit ‘use No. 3 Ignition switch
10~ Automatic free-
3; wheeling hub
I/\’ indicator light
Sub fusible link
Power-supply circuit
Main fusible link
detection circuit
Automatic free-wheeling hub
indicator control unit
[ STB Revision

AUTOMATIC FREE-WHEELING HUB INDICATOR SYSTEM - Generallnformation 8-211
3. Automatic free-wheeling hub in free condition
For the free condition, although there are (when the vehicle is traveling) output signals from the vehicle-
speed sensor, there are no signals from the pulse generator, with the result that the memory circuit is
erased (because reset signals are output from the lock-discrimination circuit), and so the indicaotr light
does not illuminate.
I
Lock Use-detection
-discrimination
Memory ipeed sensor Ignition switch
Automatic free-
detection circuit
circuit
circuit
Automatic free-wheeling
indicator control unit -
hub i
Sub fusible link
link
Pulse generator cross-sectional view PULSE GENERATOR
Coil hgnet
16W1547
rator
Front out-
put shaft
16W1546 The pulse generator is located at the rear part of the front
output shaft of the transfer, and is composed of the magnet,
the coil and the pole (iron core).
When a magnetic material (iron, nickel, etc.) is brought close
to and moved away from the pole (iron core), the magnetic flux
within the pole changes, thus generating AC voltage in the
coil.
Because the front output shaft does not rotate when the
automatic free-wheeling hub is in the free condition, there is
no generation of AC voltage in the pulse generator.
In the locked condition, however, the front output shaft and
the pulse rotor rotate, with the result that the magnetic flux
(within the p o e I (’ Iron core) of the pulse generator) changes in
accordance with the rotations of the pulse rotor, thereby
generating AC voltage in the coil.
This AC voltage is transmitted to the automatic free-wheeling
hub indicator control unit.
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8-212 AUTOMATIC FREE-WHEELING HUB lNCDlCATOR SYSTEM - $%%60n’~at’on’
Speedometer
I
iensor Vehicle-speed
sensor
16W1506
12R0058
Circuit Diagram
16W153
SPECIFICATIONS
GENERAL SPECIFICATIONS VEHICLE-SPEED SENSOR (REED-TYPE SWITCH)
The vehicle-speed sensor functions to substitute pulse signals
for the rotations (vehicle speed) of the transmission’s output
gear;/ t i is located within the speedometer.
Pulse signals are generated when the speedometer cable
rotates.
AUTbMATlC FREE-WHEELING HUB INDICATOR
CONTROL UNIT
The control unit is located at the upper part of the right cowl
side.
The control unit is composed of the pulse-detection circuit
(which receives the input signals from the pulse generator),
the vehicle-speed-detection circuit (which receives the input
signals from the vehicle-speed sensor), the lock-discrimination
circuit (which, based on both of these input signals, judges the
condition of the automatic free-wheeling hub ‘and then trans-
mits indicator output signals to the memory circuit), and the
memory circuit (which “memorizes” the indicator output
signals from the lock-discrimination circuti).
Items
Automatic free-wheeling hub indicator light
Pulse generator
Type
Vehicle-speed sensor
Type
Pulse generation
SERVICE SPECIFICATIONS
Specifications
W (SAE trade number) 1.4(74)
Magnet coil type
Reed switch type
4 pulses/ rotation
NOORG-
Items Specifications
Standard values
Pulse generator resistance
R 215-275
Vehicle-speed sensor output voltage V
When OFF 4 or more 1 STB Revision
When ON 0

AUTOMATIC FREE-WHEELING HUB INDICATOR SYSTEM -Troubleshooting 8-213
TROUBLESHOOTING NOIRH-
Inspection items
Symptom
Reference page
3-21E
0 The indicator light does not illuminate
although the automatic free-wheeling
hub is in the locked condition and the
vehicle speed is approximately 2.5 mph
(4 km/h) or higher.
0 0 0
0
The indicator light does not illuminate
when the vehicle is stopped (with the
ignition key at ON) after traveling, even
though the automatic free-wheeling hub
is in the locked condition.
The indicator light remains illuminated
when the ignition key is turned from OFF
to ON.
0
0 0 0
a 0
The indicator light remains illuminated
when (after traveling with the automatic
free-wheeling hub in the locked
condition) the vehicle is stopped, the
automatic free-wheeling hub is changed
to the free condition, and the vehicle is
then driven at a speed of approximately
2.5 mph (4 km/h) or higher.
0 Cc 0
NOTE
Number in circle indicates inspection sequence.
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8-214 AUTOM TIC FREE-WHEELING VU6 INDICATOR SYSTEM - Circuit Diagram
I
m I IA-21 m
v?~
r:
BI I To column switch
2
[Refer to P.8-461 CT
= 9’i A I
I
m z
I ’
c: d
I ’
LR
!J
I I 1
CIRCUIT DIAGRAM
AUTOMATIC FREE-WHEELING HUB INDICATOR SYSTEM
CIRCUIT
F==e=%
Battery lu-!
A-02 Sub fusible link
- 15-w r-)5-w 0.5-G
2-w
I I I I
Main fusible
link
7
N
-22
3
Pulse c:
generator
h Ignition switch
I /Locking check circuit 1
q IIEI Combination meter
Automatic free-wheeling hub
indicator control unit
1 B R
Em El1 Y L
Remark
For information concerning the ground points (example: q ),
refer to P.8-7.
37W610
Wiring color code
B: Black Br: Brown
G: Green L: Blue
LI: Light blue Lg: Light green
0: Orange P: Pink “,r: RG,‘d”Y
Y: Yellow
W: White
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AUTOMATIC FREE-WHEELING HUB INDICATOR SYSTEM - Pulse Generator 8-215
PULSE GENERATOR
REMOVAL AND INSTALLATION NOBRJM
Removal steps
I. Pulse generator
2. O-ring
NOTE
(1) Reverse the removal procedures to reinstall
(2)
q : Non-reusable parts
I 16WO92 i
l Check whether or not metal particles are adhered to the
pole (iron core) of the pulse generator.
l Check whether or not the installation bolts of the pulse
rotor or the pulse generator are loose.
(For detailed information concerning the pulse rotor, refer
to GROUP 21 TRANSMISSION - Transfer.)
CHECKING PULSE GENERATOR RESISTANCE
Check whether or not the resistance between the terminals
shown in the figure is within the standard value range.
Standard value : 215 - 275 LR
If the resistance is not within the standard value range, replace
the pulse generator.
1 STB Revision