Mitsubishi Galant. Manual — part 685

SWS DIAGNOSIS

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SIMPLIFIED WIRING SYSTEM (SWS)

54B-135

CIRCUIT OPERATION
When the passing switch is on or the front-ECU is
illuminating the headlights (high-beam), the ETACS-
ECU illuminates the high-beam indicator light.

TECHNICAL DESCRIPTION (COMMENT)
If the headlights (high-beam and passing) operate
normally, the combination meter (high-beam
indicator light bulb or printed-circuit board), the front-
ECU or the ETACS-ECU is suspected to be
defective.

TROUBLESHOOTING HINTS

•

Malfunction of the combination meter (high-beam
indicator light bulb or printed-circuit board)

•

Malfunction of the front-ECU

•

Malfunction of the ETACS-ECU

•

Damaged harness wires or connectors

DIAGNOSIS

Required Special Tool:

•

MB991223: Test Harness Set

STEP 1. Check the headlights (high-beam and passing)
operation.

Q: Do the headlights (high-beam and passing) illuminate

normally?
YES : Go to Step 2.
NO : Solve the problem first. Refer to

P.54B-9

.

AC003079 AB

CONNECTOR
BLOCK (LH)

CONNECTOR: C-66

AC003082AL

CONNECTORS: C-78, C-82

C-78

JUNCTION BLOCK
(FRONT VIEW)

C-82

AC003080AF

JUNCTION BLOCK
(REART VIEW)

CONNECTOR: C-85

SWS DIAGNOSIS

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SIMPLIFIED WIRING SYSTEM (SWS)

54B-136

STEP 2. Check the high-beam indicator light circuit at the
ETACS-ECU connector C-82.
(1)Disconnect the ETACS-ECU connector C-82 and measure

at the harness side.

(2)Connect terminal 53 to the ground.

Q: Does the high-beam indicator light illuminate?

YES : Go to Step 10.
NO : Go to Step 3.

STEP 3. Check the high-beam indicator light bulb.
Q: Is the high-beam indicator light bulb in good condition?

YES : Go to Step 4.
NO : Replace it. The high-beam indicator light should work

normally.

STEP 4. Check the combination meter (printed-circuit
board).
(1)Remove the combination meter.
(2)Remove the high-beam indicator light bulb. Then measure

the resistance between the bulb terminals.

(3)Install the bulb to the combination meter, and then measure

the resistance between connector C-29 terminal 22 and 23.
The resistance reading at this time should be much the
same as the resistance measured at Step (2).

Q: Are the two resistance values extremely different each

other?
YES : Repair or replace the combination meter (printed

circuit board). The high-beam indicator light should
work normally.

NO (much the same) : Go to Step 5.

AC002138

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

AC

CONNECTOR C-82
(HARNESS SIDE)

AC003171 AC

HIGH-BEAM INDICATOR LIGHT

AC003170

CONNECTOR C-29
(COMBINATION METER SIDE)

AB

SWS DIAGNOSIS

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SIMPLIFIED WIRING SYSTEM (SWS)

54B-137

STEP 5. Check the combination meter power supply circuit
at the combination meter connector C-29.
(1)Disconnect the combination meter connector C-29 and

measure at the harness side.

(2)Measure the voltage between terminal 23 and ground.

Q: Is the voltage approximately 12 volts (battery positive

voltage)?
YES : Go to Step 8.
NO : Go to Step 6.

STEP 6. Check combination meter connector C-29 for
damage.
Q: Is combination meter connector C-29 in good

condition?
YES : Go to Step 7.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. The high-beam

indicator light should work normally.

AC003173AB

CONNECTOR C-29
(HARNESS SIDE)

AC003089 AD

CONNECTOR: C-29

SWS DIAGNOSIS

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SIMPLIFIED WIRING SYSTEM (SWS)

54B-138

STEP 7. Check the harness wires between combination
meter connector C-29 and fusible link (1).

AC002299 AC

FUSIBLE LINK (1)

AC003089 AD

CONNECTOR: C-29

AC003082 AF

JUNCTION BLOCK
(FRONT VIEW)

CONNECTOR: C-78

AC003080AF

JUNCTION BLOCK
(REART VIEW)

CONNECTOR: C-85