1998 MITSUBISHI MONTERO Service Manual

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

Fig. 9: Rear Window & Mirror Defogger System Wiring Diagram
(Diamante)

Fig. 10: Rear Window Defogger System Wiring Diagram (Eclipse)