14.1
14.1
Heated Seats (HS)
Contents
Model 129
Page
Diagnosis
Function Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Complaint Related Diagnostic Chart . . . . . . . . . . . . . . . . . . . . . . .
11/1
12/1
Electrical Test Program
Component Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Preparation for Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21/1
22/1
23/1
b Diagnostic Manual • Body and Accessories • 03/94
14.1 HS
C/1
14.1
Heated Seats (HS)
Model 129
Diagnosis - Function Test
Test step/Test sequence
Test condition
Nominal value
O 1.0
Ignition: ON
Press front of left front seat heater
switch (S51/1) or right front seat heater
switch (S51/2) respectively.
Switch indicator lamp for stage I lights
up.
Seat cushion and backrest cushion
warm up.
23O 1.0, 2.0, 5.0, 7.0, 8.0
Ignition: ON
Press rear of left front seat heater switch
(S51/1) or right front seat heater switch
(S51/2) respectively.
Switch indicator lamp for stage II
lights up.
Seat cushion and backrest cushion
warm up noticeable more than in
stage I
23O 1.0, 2.0, 5.0, 7.0, 8.0
Switch symbol is illuminated.
23O 6.0, 9.0
O 2.0
O 3.0
1)
Seat heating stage I
Seat heating stage II
Illumination of seat heater Parking lamps switched on.
switches
Possible cause/Remedy 1)
23O 3.0, 4.0
23O 3.0, 4.0
Observe Preparation for Test, see 22.
b Diagnostic Manual • Body and Accessories • 03/94
14.1 HS
11/1
14.1
Heated Seats (HS)
Model 129
Diagnosis - Complaint Related Diagnostic Chart
Complaint/Problem
Possible cause
Entire seat heating system does not work.
Seat heat control module (N25/5) voltage supply
23 O 1.0
Left front seat cushion and backrest heating does not
operate
Seat heat control module (N25/5) voltage supply,
Left front seat heater switch (S51/1),
Left front seat cushion heating element (R13/1) and left
front backrest heating element (R13/2)
23 O 1.0
23 O 2.0
Seat heat control module (N25/5) voltage supply,
Right front seat heater switch (S51/2),
Right front seat cushion heating element (R13/3) and
right front backrest heating element (R13/4)
23 O 1.0
23 O 7.0
Indicator lamp in left front seat heater switch (S51/1) or right
front seat heater switch (S51/2) not operating.
Seat heater operates.
S51/1 indicator lamps
S51/2 indicator lamps
23 O 5.0
23 O 8.0
Illumination of left front seat heater switch (S51/1) or right front
seat heater switch (S51/2) not functioning.
S51/1 illumination
S51/2 illumination
23 O 6.0
23 O 9.0
Right front seat cushion and backrest heating does not
operate
1)
Remedy/Test step1)
23 O 3.0
23 O 4.0
Observe Preparation for Test, see 22.
b Diagnostic Manual • Body and Accessories • 03/94
14.1 HS
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14.1
Heated Seats (HS)
Model 129
Electrical Test Program - Component Locations
P82-2004-13
Figure 1
S51/1
S51/2
P54-2060-13A
Figure 2
Left front seat heater switch
Right front seat heater switch
b Diagnostic Manual • Body and Accessories • 03/94
N25/5
P82-2020-13A
Figure 3
Front HS control module
R13/1
Left front seat cushion heater element
14.1 HS
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14.1
Heated Seats (HS)
Model 129
Electrical Test Program - Component Locations
P82-0160-15
Figure 4
R13/2
Left front backrest heater element
b Diagnostic Manual • Body and Accessories • 03/94
14.1 HS
21/2
14.1
Heated Seats (HS)
Model 129
Electrical Test Program - Preparation for Test
Preparations for testing
1.
Battery voltage 11 – 14 V
2.
Fuse F1 - 12 and F1 - D ok.
Electric wiring diagram reference
See Electrical Troubleshooting Manual, Model 129
Special Tools
201 589 00 99 00
124 589 47 63 00
124 589 00 21 00
Electrical connecting set
21-pin test cable
35-pin socket box
Equipment
Multimeter 1)
1)
Fluke models 23, 83, 85, 87
Available through the MBUSA Standard Equipment Program.
b Diagnostic Manual • Body and Accessories • 03/94
14.1 HS
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14.1
Heated Seats (HS)
Model 129
Electrical Test Program - Test
Test step
Test scope
Test connection
Test condition
Nominal value
Possible cause/Remedy
DTC
O 1.0
Front HS control
module (N25/5)
Voltage supply
Circuit 30
N25/5
9w
k
c
Wiring
L 1 Ignition: OFF
11 – 14 V
L 3 Ignition: ON
11 – 14 V
Ignition: ON
11 – 14 V
N25/5
Circuit 15zx
O 2.0
Left front seat heater
switch (S51/1)
Voltage supply
9w
k
c
N25/5
9w
k
c
9w
c L 13
O 2.1,
Front HS control module (N25/5).
L 5 S51/1 Stage I held in
0–1V
depressed position
S51/1 Stage II held in
depressed position
O 2.1
Left front seat heater
switch (S51/1)
Resistance
N25/5
k
9w
b
Ignition: OFF
Disconnect test cable from
N25/5.
L 5 S51/1 Stage I held in
0–1V
>20 k]
Wiring,
Left front seat heater switch (S51/1).
0–2]
depressed position
9w
c L 13 S51/1 Stage II held in
0–2]
depressed position
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14.1 HS
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14.1
Heated Seats (HS)
Model 129
Electrical Test Program - Test
Test step
Test scope
Test connection
Test condition
Nominal value
Possible cause/Remedy
Ignition: ON
Left front seat heater switch
(S51/1) in stage II
0–1V
O 3.1,
DTC
O 3.0
Left front seat cushion heater
element (R13/1) and
N25/5
left backrest heater
k
element (R13/2)
9w c
Voltage supply
19 w c
Front HS control module (N25/5).
L8
9 – 14 V
L8
9 – 14 V
N25/5
O 3.1
9w
k
c
9w
c L 19
5–7V
9 – 14 V
k
19 w b
Ignition: OFF
Disconnect test cable from
N25/5.
L 8 R13/2
3.0 – 4.0 ]
8w
L 9 R13/1
3.0 – 4.0 ]
Resistance
N25/5
b Diagnostic Manual • Body and Accessories • 03/94
Left front seat heater switch
L 8 (S51/1) in stage I
c
Wiring,
Left front seat cushion heater
element (R13/1),
Left backrest heater element
(R13/2).
14.1 HS
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14.1
Heated Seats (HS)
Model 129
Electrical Test Program - Test
Test step
Test scope
Test connection
Test condition
Nominal value
Possible cause/Remedy
Ignition: ON
Right front seat heater
switch (S51/2) in stage II
0–1V
O 4.1,
DTC
O 4.0
Right front seat cushion
heater element (R13/3) and
right backrest heater
element (R13/4)
Voltage supply
N25/5
Front HS control module (N25/5).
9w
k
c
L2
9 – 14 V
4w
c
L2
9 – 14 V
N25/5
O 4.1
9w
k
c
L 2 switch (S51/2) in stage I
5–7V
9w
c
L4
9 – 14 V
2w
k
b
Ignition: OFF
Disconnect test cable from
N25/5.
L 4 R13/4
3.0 – 4.0 ]
9w
b
L 2 R13/3
3.0 – 4.0 ]
Resistance
N25/5
b Diagnostic Manual • Body and Accessories • 03/94
Right front seat heater
Wiring,
Right front seat cushion heater
element (R13/3),
Right backrest heater
element (R13/4).
14.1 HS
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14.1
Heated Seats (HS)
Model 129
Electrical Test Program - Test
Test step
Test scope
Test connection
Test condition
Nominal value
Possible cause/Remedy
Ignition: ON
0–1V
Wiring,
Left front seat heater switch (S51/1),
Front HS control module (N25/5).
DTC
O 5.0
Left front seat heater switch
(S51/1), indicator lamps
Voltage supply
N25/5
9w
k
c L 12 S51/1 Stage I turned on
S51/1 Stage II turned on
9w
c L 20 S51/1 Stage I turned on
S51/1 Stage II turned on
O 6.0
O 7.0
Left front seat heater switch
(S51/1), illumination
Voltage supply
Right front seat heater
switch (S51/2)
Voltage supply
S51/1
6w
c
N25/5
9w
8 – 13 V
8 – 13 V
0–1V
8 – 13 V
Disconnect plug on S51/1
L 5 Turn on parking lamps
Ignition: ON
k
c L 17 S51/2 Stage I hold
Wiring.
11 – 14 V
9 – 14 V
O 7.1,
Front HS control module (N25/5).
0–1V
depressed
9w
c L 18 S51/2 Stage II hold
0–1V
depressed
b Diagnostic Manual • Body and Accessories • 03/94
14.1 HS
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14.1
Heated Seats (HS)
Model 129
Electrical Test Program - Test
Test step
Test scope
Test connection
Test condition
Nominal value
Possible cause/Remedy
>20 k]
Wiring,
Right front seat heater
switch (S51/2).
DTC
O 7.1
Right front seat heater
switch (S51/2)
Resistance
Ignition: OFF
Disconnect test cable from
N25/5.
k
b L 17 S51/2 Stage I hold
depressed
N25/5
9w
9w
b L 18 S51/2 Stage II hold
0–2]
0–2]
depressed
O 8.0
Right front seat heater switch
(S51/2), indicator lamps
Voltage supply
9w
N25/5
Ignition: ON
k
c L 11 S51/2 Stage I turned on
S51/2 Stage II turned on
9w
c L 10 S51/2 Stage I turned on
S51/2 Stage II turned on
O 9.0
Right front seat heater switch
(S51/2), illumination
Voltage supply
6w
b Diagnostic Manual • Body and Accessories • 03/94
S51/2
c
0–1V
8 – 13 V
8 – 13 V
0–1V
8 – 13 V
Disconnect plug on S51/2
L 5 Turn on parking lamps
Wiring,
Right front seat heater switch
(S51/2),
Front HS control module (N25/5).
Wiring.
11 – 14 V
14.1 HS
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14.1
Heated Seats (HS)
Model 129
Electrical Test Program - Test
P54-2033-13
Figure 1
X30
P54-2035-13A
Figure 2
Accessory equipment connector block (5-pole)
b Diagnostic Manual • Body and Accessories • 03/94
X55/3
X55/4
Left ESA connector block
Right ESA connector block
14.1 HS
23/6