1997 MERCEDES-BENZ ML350 fuse box diagram

TESTS.
Normal Ventilation In Regulating Mode
To check normal ventilation in regulating mode, set temperature selector knob to White range (vertical). Set
mode control knob to 4-o'clock position. Ensure A/C button indicator is illuminated. Air will vent from upper
and lower outlets and A/C compressor will engage. Ambient air will flow from center outlet and coolant
circulation pump will operate. If operation is not as specified, perform the following in order:
Check A/C button activation. See A/C BUTTON under ELECTRICAL TESTS.
Check A/C pressure switch. See A/C REFRIGERANT PRESSURE SWITCH under ELECTRICAL
TESTS.
Economy Setting Not In Heating Mode
To check economy setting without heating mode activated, set temperature selector knob to Blue range. Set
mode control knob to the 9-o'clock position. Ensure A/C button indicator is not illuminated. Ambient air will
flow from center outlet and A/C compressor will NOT be engaged. If operation is not as specified, perform the
following:
Check A/C button activation. See A/C BUTTON under ELECTRICAL TESTS.
Economy Setting In Heating Mode
To check economy setting with heating mode activated, set temperature selector knob to Red range. Set mode
control knob to the 4-o'clock position. Ensure A/C button indicator is not illuminated. Heated air will flow from
lower, upper and center outlets and A/C compressor will NOT be engaged. If operation is not as specified,
perform the following:
Check A/C button activation. See A/C BUTTON under ELECTRICAL TESTS.
Recirculation Mode
To check recirculation mode, press fresh/recirculation button. Ensure fresh/recirculation indicator is
illuminated. Set blower speed knob to position No. 4. Blower fan noise will increase noticeably. If operation is
not as specified, check wiring between recirculated air flap element, heater-A/C switch and No. 16 fuse (15-
amp).
ELECTRICAL TESTS
Voltage Supply Circuit Z50/2
1. Connect socket box to A/C push button control unit and wiring harness. See CONNECTING TEST
EQUIPMENT . Turn ignition on, with engine off. Connect voltmeter positive lead to socket box terminal
No. 7 and negative lead to terminal No. 9.
2. Voltage should be 11-14 volts. If voltage is not as specified, check voltage supply circuit Z50/2 between
No. 16 fuse (15-amp) and connected components. See WIRING DIAGRAMS
. Repair as necessary.

2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
me
Saturday, October 02, 2010 3:25:10 PMPage 10 © 2006 Mitchell Repair Information Company, LLC.

blend air flap actuator motor.
6. Turn ignition off. Disconnect test cable from A/C push button control unit. Connect ohmmeter positive
lead to socket box terminal No. 1 and negative lead to terminal No. 8. Resistance should be 120 ohms.
7. If resistance is not as specified, check blend air flap actuator motor circuits. See WIRING DIAGRAMS
.
Repair as necessary. If circuits are okay, replace blend air flap actuator motor.
A/C Button
1. Connect socket box to A/C push button control unit and wiring harness. See CONNECTING TEST
EQUIPMENT . Connect voltmeter positive lead to socket box terminal No. 10 and negative lead to
terminal No. 9.
2. Turn ignition on. Depress A/C button switch to on position and set blower speed knob to position No. 4.
Ensure A/C button indicator is illuminated. Voltage should be less than one volt. Depress A/C button
switch to off position with A/C button indicator not illuminated or set blower speed knob to off position.
Voltage should be 11-14 volts.
3. If voltage is as specified, go to next step. If voltage is not as specified, check A/C button wiring harness
circuits. See WIRING DIAGRAMS
. Repair as necessary. If circuits are okay, replace A/C button
switch.
4. Turn ignition on. Depress A/C button switch to on position and set blower speed knob to position No. 4.
Ensure A/C button indicator is illuminated. Connect voltmeter positive lead to socket box terminal No. 4
and negative lead to terminal No. 9. Voltage should be more than 3.0 volts.
5. Connect Fused Jumper Wire (124 589 37 63 00) between socket box terminals No. 4 and 11. Depress A/C
button switch to on position and set blower speed knob to position No. 4. Ensure A/C button indicator is
illuminated. Measure voltage. Voltage should be less than one volt.
6. If voltage is not as specified, check A/C button wiring harness circuits. See WIRING DIAGRAMS
.
Repair as necessary. If circuits are okay, replace A/C button switch.
A/C Refrigerant Pressure Switch
1. Turn ignition off. Disconnect refrigerant pressure sensor connector. Turn ignition on. Connect voltmeter
positive lead to pressure sensor harness connector terminal "B" (Pink wire) and negative lead to terminal
"A" (Tan wire). Voltage should be 4.75-5.25 volts.
2. If voltage is as specified, replace A/C refrigerant pressure sensor. If voltage is not as specified, check
wiring harness between refrigerant pressure sensor and All Activity Module (AAM). See WIRING
DIAGRAMS . Repair as necessary. If circuits are okay, replace AAM and retest A/C system.
Outside Temperature Sensor
1. Connect socket box to A/C push button control unit and wiring harness. See CONNECTING TEST
EQUIPMENT . Turn ignition off. Connect ohmmeter positive lead to socket box terminal No. 12 and
negative lead to terminal No. 3.
2. Disconnect test cable from A/C push button control unit. See OUTSIDE TEMPERATURE SENSOR
RESISTANCE table. If resistance is not as specified, check wiring harness between outside temperature
sensor and A/C push button control unit. See WIRING DIAGRAMS
. Repair as necessary. If wiring
harness is okay, replace outside temperature sensor.

2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
me
Saturday, October 02, 2010 3:25:10 PMPage 13 © 2006 Mitchell Repair Information Company, LLC.

AF54.30-P-8400A
Instrument cluster indicates: Oil sensor defective, oil level below min. or oil level

above max. with engine running and at operating temperature. No DTC stored.
19.5.98

MODEL
129.0, 163.1, 202.0, 208.3 /4, 210.0 /2 /6, 220.0 /1 with ENGINE 112

MODEL
129.0, 163.1, 202.0, 208.3 /4, 210.0 /2, 220.0 /1 with ENGINE 113

Damage code
Cause
Remedy

54 201 90
Oil low, connector defective or coding error
1
Shut off engine and wait 2 min. (key

position 0)

Instrument cluster indicates oil sensor

defective, oil level below min. or oil level

above max. with engine warm and running.

No DTC stored in DTC memory!

2
Check oil level with oil dipstick

3
Check oil level on instrument cluster:

- Key in steering wheel lock position 2,

engine not running

- Wait until - - - - - - appears on

instrument cluster

- When this is displayed press the reset

button for the tripodometer twice within

1 sec. (display appears only after

expiration of a waiting time (max. 30

min.) depending on engine oil

temperature)

Oil level is at bottom mark on oil dipstick

and instrument cluster indicates:
-1L
, -
1,5L
or -2L
#
4
Add quantity of oil indicated on

instrument cluster display and repeat

test.

Oil level at upper mark on dipstick and

instrument cluster indicates either oil level

okay or -1L
, -
1,5L
, -2L

#
5
Recode instrument cluster

AF54.30-P-8600A

Problem still present
#
6
Check cable to oil sensor, oil sensor
connectors, control module and fuse

box (see wiring diagram) for good contact

Copyright DaimlerChrysler AG 05.06.2006 CD-Ausgabe G/10/04 . This WIS print-out will not be recorde
d by Modification services.
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