MITSUBISHI MONTERO 1998 Service Manual

Fig. 9: TP Sensor Connector Terminals (All Other Models)
Courtesy of Mitsubishi Motor Sales of America

DEFOGGER - REAR WINDOW
1998 Mitsubishi Montero
1998 ACCESSORIES & EQUIPMENT
Mitsubishi - Rear Window Defoggers
Diamante, Eclipse, Galant, Mirage, Montero, Montero Sport,
3000GT
DESCRIPTION & OPERATION
Rear window defogger is a heating filament grid bonded to
inside of window. Rear window defogger is controlled by defogger
switch on instrument panel and a defogger relay.
On Montero, a timer relay controls defogger operation for 9-
11 minutes, then turns defogger off. On Eclipse and Galant, defogger
timer circuit is integral with Electronic Timer Alarm Control System
(ETACS) ECU. Timer will operate defogger for 11 minutes then turn off,\
even with defogger switch in ON position and indicator light
illuminated. On Diamante, timer will operate defogger for 20 minutes,
then turn off.
COMPONENT LOCATIONS
COMPONENT LOCATIONS TABLE








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Component Location
A/C ECU
Diamante ......................... Behind Center Of Dash
Data Link Connector (DLC) ....... Under Left Side Of Dash,
Near Steering Column
Defogger Relay
Montero Sport ....................... Under Left Side Of
Glove Compartment
Except Montero Sport ................... On Relay Block,
Behind Left Side Of Dash
Defogger Timer
Diamante ......................... Integral With A/C ECU
Eclipse & Galant ............... Integral With ETACS-ECU
Montero ...................... Behind Left Side Of Dash,
Behind Speaker
ETACS-ECU ......................... Above Left Kick Panel,
On Junction Block









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TROUBLE SHOOTING
* PLEASE READ THIS FIRST *
NOTE: For additional trouble shooting information on Eclipse and
Galant, see SYMPTOM TESTS.
DEFOGGER DOES NOT WORK
Check for blown fuse, poor contact, defective defogger
switch, poor connection or open wire.
DEFOGGER TIMER INOPERATIVE

Check defogger switch or defogger timer. See COMPONENT TESTS.
INDICATOR LIGHT DOES NOT WORK
Check for burned out bulb, open circuit or poor connection.
INDICATOR LIGHT IS DIM
Check rheostat or indicator bulb.
SYMPTOM TESTS
INPUT SIGNAL INSPECTION
NOTE: The following information only applies to Eclipse and Galant.
NOTE: Perform input signal inspection before proceeding with
SYSTEM TESTS .
Eclipse & Galant
1) Input signal inspection can be performed using scan tool
or an analog voltmeter. To perform inspection using scan tool, go to
next step. To perform inspection using an analog voltmeter, go to step
3).
2) Turn ignition off. Connect scan tool to Data Link
Connector (DLC). Turn ignition on and then off. If buzzer on scan tool\
sounds when ignition was turned on, ECU input signal is normal. If
buzzer did not sound, go to SYSTEM TESTS.
3) Turn ignition off. Connect DTC Check Harness (MB991529) t\
o
DLC terminals No. 4 or 5 (ground) and terminal No. 9. See Fig. 1.
Connect voltmeter leads to check harness leads. Turn ignition switch
on, then off. If voltmeter deflects once when ignition was turned on,
ECU input signal is normal. If voltmeter did not deflect, go to
SYSTEM TESTS .
Fig. 1: Identifying Data Link Connector (DLC) Terminals
Courtesy of Mitsubishi Motor Sales of America
SYSTEM TESTS

NOTE: The following information only applies to Eclipse and Galant.
NOTE: Perform INPUT SIGNAL INSPECTION before proceeding with
SYSTEM TESTS. To identify circuit connector terminals, see
WIRING DIAGRAMS .
Communication With All Systems Not Possible (Eclipse &
Galant)
1) Check voltage between ground and Data Link Connector (DLC)\
terminal No. 16 (Red/Black wire on Eclipse or Brown/Red wire on
Galant). See Fig. 1. If battery voltage is present, go to step 3). If
battery voltage is not present, go to next step.
2) Check junction block connectors between DLC and power
supply. See WIRING DIAGRAMS . If connectors are okay, check circuit
between power supply and DLC. See WIRING DIAGRAMS. Repair as
necessary.
3) Check continuity between ground and DLC terminals No. 4
and 5. If continuity is present, replace scan tool and retest. If
continuity is not present, check circuit between ground and DLC. See
WIRING DIAGRAMS . Repair as necessary.
Communication With One-Shot Pulse Input Signal Only Is Not
Possible (Eclipse & Galant)
Check circuit between DLC and junction block No. 1. See
WIRING DIAGRAMS . Repair as necessary. If circuit is okay, check
harness connectors to ETACS-ECU, DLC and junction/joint connectors.
Repair as necessary. If connectors are okay, replace ECU.
Defogger Does Not Operate With Defogger Switch ON (Eclipse &
Galant)
1) Check defogger switch input signal. See
INPUT SIGNAL INSPECTION . If switch input signal is okay, check
defogger circuit and relay. See DEFOGGER RELAY TEST under COMPONENT
TESTS. Repair or replace as necessary. If switch input signal is not
okay, go to next step.
2) Check defogger switch. See DEFOGGER SWITCH TEST under
COMPONENT TESTS. Replace as necessary. If defogger switch is okay,
turn ignition on. Check voltage between ground and defogger switch
harness-side connector terminal No. 4 (Eclipse) or terminal No. 2
(Galant). See WIRING DIAGRAMS . If voltage reading is 5 volts (Eclipse)
or battery voltage (Galant), go to next step. If voltage reading is
not as specified, go to step 4).
3) Check joint/junction connectors between switch, instrument
panel cluster and ETACS-ECU. See WIRING DIAGRAMS. Repair as necessary.
If connectors are okay, check circuit between defogger switch and
ground. Repair as necessary. If circuit is okay, replace ECU.
4) Check harness connectors to ETACS-ECU and instrument panel
cluster. Repair as necessary. If connectors are okay, check circuit
between ECU and defogger switch. Repair as necessary.
Defogger Relay Circuit System Check (Eclipse & Galant)
1) Check defogger relay. See DEFOGGER RELAY TEST under
COMPONENT TESTS. Replace as necessary. If relay is okay, go to next
step.
2) Check voltage between ground and relay harness-side
connector terminals No. 3 and 5. See WIRING DIAGRAMS. If battery
voltage is present, go to next step. If battery voltage is not
present, go to step 4).
3) Check harness connectors to relay, ETACS-ECU, junction
block and rear wiring/liftgate. See WIRING DIAGRAMS. Repair as
necessary. If connectors are okay, check circuit between defogger
relay and rear defogger, defogger and ground, or defogger relay and
ECU. See WIRING DIAGRAMS . Repair as necessary. If circuits are okay,

replace ECU.
4) Check harness connectors to junction block and ignition
switch. Repair as necessary. If connectors are okay, check circuit
between ignition switch and junction block, and between fusible link
No. 2 and junction block. See WIRING DIAGRAMS. Repair as necessary.
COMPONENT TESTS
DEFOGGER RELAY TEST
Diamante & Eclipse
1) Remove defogger relay. See COMPONENT LOCATIONS. Ground
relay terminal No. 1, and apply battery voltage to terminal No. 3. See
Fig. 2 . Check relay continuity using ohmmeter.
2) Continuity should exist between terminals No. 2 and 5.
With voltage disconnected, continuity should not exist between
terminals No. 2 and 5. Ensure continuity exists between terminals No.
1 and 3. If continuity is not as specified, replace relay.
Galant, Mirage & Montero Sport
1) Remove defogger relay. See COMPONENT LOCATIONS. Ground
relay terminal No. 3, and apply battery voltage to terminal No. 1. See
Fig. 2 . Check relay continuity using ohmmeter.
2) Continuity should exist between terminals No. 2 and 5.
With voltage disconnected, continuity should not exist between
terminals No. 2and 5. Ensure continuity exists between terminals No. 1
and 3. If continuity is not as specified, replace relay.
Montero
1) Remove defogger relay. See COMPONENT LOCATIONS. Ground
relay terminal No. 3 and apply battery voltage to terminal No. 1. See
Fig. 3 . Check relay continuity using ohmmeter.
2) Continuity should exist between terminals No. 4 and 5.
With voltage disconnected, continuity should not exist between
terminals No. 4and 5. Ensure continuity exists between terminals No. 1
and 3. If continuity is not as specified, replace relay.
3000GT
1) Remove defogger relay. See COMPONENT LOCATIONS. Ground
relay terminal No. 3, and apply battery voltage to terminal No. 5. See
Fig. 4 . Check relay continuity using ohmmeter.
2) Continuity should exist between terminals No. 1 and 2.
With voltage disconnected, continuity should not exist between
terminals No. 1and 2. Ensure continuity exists between terminals No. 3
and 5. If continuity is not as specified, replace relay.
Fig. 2: Identifying Defogger Relay Terminals (Diamante, Eclipse,
Galant, Mirage & Montero Sport)
Courtesy of Mitsubishi Motor Sales of America

Fig. 3: Identifying Defogger Relay Terminals (Montero)
Courtesy of Mitsubishi Motor Sales of America
Fig. 4: Identifying Defogger Relay Terminals (3000GT)
Courtesy of Mitsubishi Motor Sales of America
DEFOGGER SWITCH TEST

NOTE: Remove window defogger switch and disconnect switch
connector for the following test.
Diamante
Rear window defogger is integral with and controlled by A/C
system ECU. To diagnose system, refer to AIR CONDITIONING & HEATING
SERVICE & REPAIR article.
Eclipse
Turn defogger switch to OFF position. Using ohmmeter, check
switch continuity. Continuity should be present between terminals No.
1 and 3, and terminals No. 2 and 6. Turn defogger switch to ON
position. Continuity should be present between terminals No. 1, 3 and
4, and between terminals No. 2 and 6. See Fig. 5. If continuity is not
as specified, replace switch.
Galant
Turn defogger switch to OFF position. Using ohmmeter, check
switch continuity. Continuity should be present between terminals No.
1 and 3. Turn defogger switch to ON position. Continuity should exist
between terminals No. 2, 4 and 6, and between terminals No. 1 and 3.
See Fig. 5 . If continuity is not as specified, replace switch.
Mirage
Turn defogger switch to OFF position. Using ohmmeter, check
switch continuity. Continuity should be present between terminals No.
1 and 3, and terminals No. 2 and 6. Turn defogger switch to ON
position. Continuity should exist between terminals No. 1 and 3, and
terminals No. 2, 4, 5 and 6. See Fig. 5. If continuity is not as
specified, replace switch.
Montero
Turn defogger switch to OFF position. Using ohmmeter, check
switch continuity. Continuity should be present between terminals No.
1 and 3, and terminals No. 4 and 5. Turn defogger switch to ON
position. Continuity should exist between terminals No. 1 and 3,
terminals No. 4 and 5, and between terminals No. 2 and 6. See Fig. 5.
If continuity is not as specified, replace switch.
Montero Sport
Turn defogger switch to OFF position. Using ohmmeter, check
switch continuity. Continuity should be present between terminals No.
1 and 5, and terminals No. 2 and 6. Turn defogger switch to ON
position. Continuity should be present between terminals No. 3 and 4,
terminals No. 1 and 5, and between terminals No. 2 and 6. See Fig. 5.
If continuity is not as specified, replace switch.
3000GT
1) Remove defogger switch assembly from instrument cluster
bezel. With defogger switch in OFF position, check switch continuity
using ohmmeter.
2) Continuity should exist between terminals No. 3 and 4.
With defogger switch in ON position, continuity should exist between
terminals No. 1 and 2, terminals No. 1 and 6, and between terminals
No. 3 and 4. See Fig. 6. If continuity is not as specified, replace
switch.
Fig. 5: Identifying Defogger Switch Terminals (Eclipse, Galant,
Mirage, Montero & Montero Sport)
Courtesy of Mitsubishi Motor Sales of America

Fig. 6: Identifying Defogger Switch Terminals (3000GT)
Courtesy of Mitsubishi Motor Sales of America
DEFOGGER TIMER TEST
Montero
Remove defogger timer from interior relay block. Connect test
battery and test light to timer. See Fig. 7. Ensure test light
illuminates for about 11 seconds when battery voltage is applied to
terminal No. 3. Reapply battery voltage to terminal No. 3 and observe
test light. Test light should go off. If timer does not test as
specified, replace timer.
Fig. 7: Identifying Defogger Timer Terminals (Montero)
Courtesy of Mitsubishi Motor Sales of America
GRID TEST

1) Start and run engine at 2000 RPM. Ensure battery is fully
charged. Turn defogger switch to ON position. Using a voltmeter, check
voltage at center section of each defogger grid filament.
2) If voltage is about 6 volts, grid filament is okay. If
voltage is about 12 volts, an open is present in negative circuit.
Move probe slowly toward negative terminal to determine location of
open circuit.
3) If voltage is zero volts, an open is present in positive
circuit. Move probe slowly toward positive terminal to determine
location of open circuit. Repair grid as necessary. See
GRID FILAMENT REPAIR under ON-VEHICLE SERVICE.
ON-VEHICLE SERVICE
GRID FILAMENT REPAIR
Clean broken wire tips thoroughly. Place masking tape along
both sides of broken wire. See Fig. 8. Apply Repair Paste (DuPont
4817) to broken section of grid. Remove masking tape after paste has
dried. Wait 24 hours before using defogger.
Fig. 8: Repairing Rear Defogger Grid Element
REMOVAL & INSTALLATION
DEFOGGER SWITCH
Removal & Installation (Diamante)
Defogger switch is integral with A/C system ECU. To remove
A/C ECU, remove center console. Remove audio panel. Remove radio.
Remove A/C ECU. To install, reverse removal procedure.
Removal & Installation (Eclipse)
Remove upper stoppers from glove compartment. Drop down glove
compartment. From glove compartment opening, reach behind center air
outlet assembly and disconnect harness connectors to switches. Release
metal clips from center air outlet assembly. Remove center air outlet.
Remove defogger switch from center air outlet. To install, reverse
removal procedure.
Removal & Installation (Galant)

At heater unit, remove center air outlet cool air by-pass
lever cable from damper lever. To remove center air outlet, push
springs at bottom of center air outlet upward. Outlet is located above
radio. Remove switch from center air outlet. To install, reverse
removal procedure. Turn cool air by-pass lever on outlet fully upward.
Pull air by-pass lever fully downward and install cool air by-pass
lever cable to damper lever.
Removal & Installation (Mirage)
Remove driver-side lower dash panel. Remove center console
assembly and foot distribution duct. Disconnect rear window defogger
switch harness connector. Remove switch. To install, reverse removal
procedure.
Removal & Installation (Montero)
Remove defogger switch by prying switch off instrument
cluster bezel. Disconnect wiring harness from defogger switch. Remove
switch. To install, reverse removal procedure.
Removal & Installation (Montero Sport)
Remove instrument cluster bezel. Bezel is held in by metal
clips. Disconnect wiring harness from defogger switch. Remove switch
from behind bezel. To install, reverse removal procedure.
Removal & Installation (3000GT)
Remove knee protector. Remove steering column upper and lower
covers. Remove instrument cluster bezel. Disconnect wiring harness
from defogger switch. Remove defogger switch. To install, reverse
removal procedure.
WIRING DIAGRAMS