1991 MITSUBISHI MONTERO Service Manual

FUEL GAUGE
Simple Test
Disconnect fuel sending unit connector wire in luggage
compartment, cargo space, or at tank unit. Connect a 12-volt, 3.4-watt
bulb to harness side of connector, between power terminal and ground
(Yellow and Black wires on Montero). On Pickup and Ram-50 see Fig. 1.
Turn ignition switch to ON position. Ensure test bulb flashes, or
stays on, and fuel gauge needle moves. If bulb or gauge needle does
not function as described, check and repair fuel gauge circuit.
CAUTION: Gauge coils can be damaged if wire is grounded too long.
Perform test as quickly as possible.
Fig. 1: Identifying Fuel Gauge Test Connection (Pickup & Ram-50)
Courtesy of Chrysler Motors.
NOTE: The following test must be completed with instrument panel
cluster removed. Use ohmmeter for all measurements. If
resistance is extremely low, there may be a short in the
coil. If resistance is extremely high, there may be a broken
wire or similar problem in the gauge.
Resistance Test
Remove instrument cluster. See INSTRUMENT CLUSTER under
REMOVAL & INSTALLATION. Measure resistance between appropriate
terminals of instrument cluster or combination gauges. See Fig. 2 or

Fig. 3. See FUEL GAUGE RESISTANCE SPECIFICATIONS table. If resistance
readings are not to specifications, replace fuel gauge.
FUEL GAUGE RESISTANCE SPECIFICATIONS TABLE









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Application Terminals Ohms
Montero .................... No. 1 & 2 ........................ 55
" .......................... No. 2 & 3 ....................... 165
" .......................... No. 1 & 3 ....................... 110
Pickup & Ram-50 .......... IGN & ground. ................... 62-78
" ........................... 7V & FU ...................... 49-61









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Fig. 2: Fuel Gauge Resistance Check Terminal ID (Montero)
Courtesy of Mitsubishi Motor Sales of America.
Fig. 3: Fuel Gauge Resistance Check Terminal ID (Pickup & Ram-50)
Courtesy of Mitsubishi Motor Sales of America.

OIL PRESSURE GAUGE
Circuit Test
Disconnect oil pressure gauge wiring connector from sending
unit inside the engine compartment. Connect a 12-volt test light
between harness connector terminal and ground. Turn ignition on, but
DO NOT start engine. If test light comes on and gauge needle moves, go
to GAUGE RESISTANCE TEST. If test light does not come on and gauge
needle does not move, repair wiring to sending unit.
Gauge Resistance Test
Remove instrument cluster from instrument panel. See
INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Check continuity
between oil pressure gauge terminals. See Fig. 4 or Fig. 5. See
OIL PRESSURE GAUGE RESISTANCE SPECIFICATIONS table. If resistance is
not within specification, replace oil pressure gauge.
OIL PRESSURE GAUGE RESISTANCE SPECIFICATIONS TABLE









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Application Ohms
Montero ...................................... 50
Pickup & Ram-50 ........................... 37-47









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Fig. 4: Oil Pressure Gauge Test Terminal ID (Pickup & Ram-50)
Courtesy of Chrysler Motors

Fig. 5: Oil Pressure Gauge Test Terminal ID (Montero)
Courtesy of Chrysler Motors
REED SWITCH
Continuity Check (Except Pickup & Ram-50)
Remove instrument cluster. See INSTRUMENT CLUSTER under
REMOVAL & INSTALLATION. Check continuity between reed switch terminals
No. 1 and 2. See Fig. 6. Ensure continuity pulses on and off 4 times
per revolution of speedometer shaft connection. If continuity is not
as specified, replace reed switch.
Fig. 6: Identifying Reed Switch Test Terminals (Montero)
Courtesy of Mitsubishi Motor Sales of America.
SPEEDOMETER

Calibration Test
Adjust tire pressure to standard value. Using a calibrated,
reliable speedometer tester, compare reading of vehicle speedometer to
speedometer tester. See SPEEDOMETER ALLOWABLE VARIATION table. Replace
speedometer if necessary.
SPEEDOMETER ALLOWABLE VARIATION TABLE









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MPH (km/h) Allowable Variation MPH (km/h)
20 (32) .......................... 19-22 (31-35)
40 (64) .......................... 38-44 (61-71)
60 (97) ......................... 57-66 (92-106)
80 (129) ....................... 76-88 (122-142)
100 (161) ..................... 94-110 (151-177)









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TACHOMETER
NOTE: DO NOT reverse polarity when installing tachometer, as diode
and transistor may be damaged.
Calibration Test
Connect a calibrated, reliable tach-dwell meter to vehicle
ignition system. Operate engine at various speeds (RPM). See
TACHOMETER ALLOWABLE VARIATION table. If comparison between tach-dwell
meter and vehicle tachometer readings do not fall in the standard
range of permissible variation, replace vehicle tachometer.
TACHOMETER ALLOWABLE VARIATION TABLE









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Engine Speed (RPM) Allowable Variation (RPM)
1000 .................................. 900-1100
3000 ................................. 2850-3150
5000 ................................. 4750-5250
6000 ................................. 5700-6300









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TEMPERATURE GAUGE
CAUTION: DO NOT connect sender wire directly to ground during test.
Circuit Test
Disconnect temperature sender wire from sending unit. Connect
a 12-volt, 3.4-watt test bulb between connector terminal and ground.
Turn ignition switch to ON position. If test bulb flashes and
temperature gauge needle moves, go to SENSOR RESISTANCE TEST. If test
light does not flash and gauge needle does not move, repair wiring to
sending unit.
Sensor Resistance Test
Remove thermosensor (sending unit) from engine block. Place
sending unit in hot water of 158
F (70C) temperature. Check sensor
resistance with an ohmmeter. Thermosensor resistance should be 90-117
ohms at 158
F (70C). If thermosensor resistance in okay, go to GAUGE
RESISTANCE TEST. Replace thermosensor if resistance is not as
specified.
Gauge Resistance Test
Remove instrument cluster from instrument panel. See
INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Measure resistance
between temperature gauge terminals at rear of cluster or combination

gauges. See TEMPERATURE GAUGE RESISTANCE SPECIFICATIONS table. See
Fig. 7 or Fig. 8.
Fig. 7: Temperature Gauge Test Terminals (Montero)
Courtesy of Mitsubishi Motor Sales of America.
Fig. 8: Temperature Gauge Test Terminal ID (Pickup & Ram-50)
Courtesy of Mitsubishi Motor Sales of America.
TEMPERATURE GAUGE RESISTANCE SPECIFICATIONS TABLE









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Application Terminals Ohms
Montero ............... No. 1 & 2 ......... 55
Pickup & Ram-50 ........ 7V & TU ....... 49-61









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VOLTMETER
Resistance Test (Montero)
Using an ohmmeter, measure resistance between voltmeter
terminals. See Fig. 9. Resistance should be 380-460 ohms.
Fig. 9: Identifying Voltmeter Resistance Test Terminals (Montero)
Courtesy of Mitsubishi Motor Sales of America.
Voltage Test (Pickup & Ram-50)
Using a voltmeter, connect positive lead to terminal No. 7 of
fuse box, and ground negative terminal. Crank engine and compare
readings of vehicle voltmeter to testing voltmeter. Voltage variation
should not exceed 0.5 volt (plus or minus). Replace voltmeter if
voltage reading is not as specified.
REMOVAL & INSTALLATION
INSTRUMENT CLUSTER
Removal & Installation (Montero)
1) Remove instrument cluster cover. Remove screws from bottom
of instrument cluster. Remove bolt from upper part of cluster.
2) Disconnect speedometer cable from back of instrument
cluster by pushing stopper of plug on speedometer cable side of
connection. Pull cluster out part way. Disconnect all connectors
attaching cluster. Remove cluster. See Fig. 10. To install, reverse
removal procedure.

Fig. 10: Identifying Instrument Cluster Components (Montero)
Courtesy of Mitsubishi Motor Sales of America.
Removal & Installation (Pickup & Ram-50)
1) Disconnect negative battery cable. Remove heater fan