![](../../../logos/other/rarrd.gif) |
Test scope |
Test connection |
Test condition |
Nominal value |
Possible cause/Remedy |
1.0 |
Left front seat
Seat heater relay
(stage 1) (K59)
Function |
|
|
|
Replace seat heater relay (stage
1) (K59) with relay of same type i.e. with right seat heater relay
(K59).
Start engine.
HHT activation:
Stage 1
![](../../../logos/mb/ufdg.gif)
![](../../../logos/mb/ufdg.gif) ![](../../../logos/mb/twodg.gif) |
![](../../../logos/mb/uodg.gif)
Relay (K59) is activated.
![](../../../logos/mb/uodg.gif) ![](../../../logos/mb/ufdg.gif)
|
If the values are OK:
K59
If the values are not OK:
1.1 |
1.1 |
Left front seat
Seat heater relay
(stage 1) (K59)
Activation |
2 ![](../../../logos/mb/sockr.gif) |
K59
![](../../../logos/mb/volmmc.gif)
|
![](../../../logos/mb/sockl.gif) 1
|
Remove relay (K59) from its socket.
Start engine.
HHT activation:
Stage 1
![](../../../logos/mb/ufdg.gif) ![](../../../logos/mb/uidg.gif) |
![](../../../logos/mb/uodg.gif)
11 - 14 V
|
Wiring,
1.2 |
1.2 |
Left front seat
Seat heater relay
(stage 1) (K59)
Activation |
B3
|
X55/3
![](../../../logos/mb/volmmc.gif)
|
![](../../../logos/mb/sockl.gif) B5
|
Disconnect X55/3 connector.
Start engine.
HHT activation:
Stage 1
![](../../../logos/mb/ufdg.gif) ![](../../../logos/mb/uidg.gif) |
![](../../../logos/mb/uodg.gif)
11 - 14 V
|
Wiring. |
2.0
|
Left front seat
Seat heater relay
(stage 2) (K59/1)
Function |
|
|
|
Replace seat heater relay (stage
2) (K59/1) with relay of same type i.e. with right seat heater relay
(K59/1).
Start engine.
HHT activation:
Stage 2
![](../../../logos/mb/ufdg.gif)
![](../../../logos/mb/ufdg.gif) ![](../../../logos/mb/foudg.gif) |
![](../../../logos/mb/uodg.gif)
Relay (K59/1) is activated.
![](../../../logos/mb/uodg.gif) ![](../../../logos/mb/ufdg.gif)
|
If the values are OK:
K59/1
If the values are not OK:
2.1 |
2.1 |
Left front seat
Seat heater relay
(stage 2) (K59/1)
Activation |
2 ![](../../../logos/mb/sockr.gif) |
K59/1
![](../../../logos/mb/volmmc.gif)
|
![](../../../logos/mb/sockl.gif) 1
|
Remove relay (K59/1) from its socket.
Start engine.
HHT activation:
Stage 2
![](../../../logos/mb/ufdg.gif) ![](../../../logos/mb/thrdg.gif) |
![](../../../logos/mb/uodg.gif)
11 - 14 V
|
Wiring,
2.2 |
2.2 |
Left front seat
Seat heater relay
(stage 2) (K59/1)
Activation |
B4
|
X55/3
![](../../../logos/mb/volmmc.gif)
|
![](../../../logos/mb/sockl.gif) B5
|
Disconnect X55/3 connector.
Start engine.
HHT activation:
Stage 2
![](../../../logos/mb/ufdg.gif) ![](../../../logos/mb/thrdg.gif) |
![](../../../logos/mb/uodg.gif)
11 - 14 V
|
Wiring. |
3.0 |
Left front seat heater switch
(S51/1)
Function |
![](../../../logos/mb/elgrou.gif) ![](../../../logos/mb/sockr.gif) |
|
N10
![](../../../logos/mb/sockl.gif) B12
(4)
|
Disconnect connect 4 at N10
Press switch (S51/1):
Heating stage 1
Heating stage 2 |
< 1
approx. 470
|
Wiring,
S51/1 |
4.0 |
Left front seat heater
Voltage supply |
B6 ![](../../../logos/mb/sockr.gif) |
X55/3
![](../../../logos/mb/volmmc.gif)
|
![](../../../logos/mb/sockl.gif) B5
|
Disconnect connect X55/3
Ignition: ON |
11 - 14 V
|
Wiring,
Convenience relay (F1k14) |
5.0 |
LF/RF seat cushion/backrest heater
element (R13/1, R13/2)
(stage 1)
Voltage supply
|
X54/9
B ![](../../../logos/mb/sockr.gif) |
|
X54/10
![](../../../logos/mb/sockl.gif) B
|
Disconnect connect X54/9 and X54/10
Start engine.
HHT activation
Stage 1
![](../../../logos/mb/ufdg.gif)
|
![](../../../logos/mb/uodg.gif)
11 - 14 V
|
Wiring. |
5.1 |
LF/RF seat cushion heater element
(R13/1, R13/2)
(stage 2)
Voltage supply
|
X54/9
B ![](../../../logos/mb/sockr.gif) |
|
X54/9
![](../../../logos/mb/sockl.gif) A
|
Disconnect connect X54/9
Start engine.
HHT activation:
Stage 2
![](../../../logos/mb/ufdg.gif)
|
![](../../../logos/mb/uodg.gif)
11 - 14 V
|
Wiring. |
6.0 |
LF seat cushion heater element
(R13/1)
Resistance
|
X54/9
A ![](../../../logos/mb/sockr.gif) |
|
X54/9
![](../../../logos/mb/sockl.gif) B
|
Disconnect connector X54/9
|
5 - 10
|
Wiring,
R13/1 |
6.1 |
LF backrest heater element (R13/2)
Resistance
|
X54/10
A ![](../../../logos/mb/sockr.gif) |
|
X54/10
![](../../../logos/mb/sockl.gif) B
|
Disconnect connector X54/10
|
5 - 10
|
Wiring,
R13/2 |
7.0 |
Right front seat
Seat heater relay
(stage 1) (K59)
Function |
|
|
|
Replace seat heater relay (stage
1) (K59) with relay of same type i.e. with left seat heater relay
(K59).
Start engine.
HHT activation:
Stage 1
![](../../../logos/mb/ufdg.gif)
![](../../../logos/mb/ufdg.gif) ![](../../../logos/mb/twodg.gif) |
![](../../../logos/mb/uodg.gif)
Relay (K59) is activated.
![](../../../logos/mb/uodg.gif) ![](../../../logos/mb/ufdg.gif)
|
If the values are OK:
K59
If the values are not OK:
7.1 |
7.1 |
Right front seat
Seat heater relay
(stage 1) (K59)
Activation |
2 ![](../../../logos/mb/sockr.gif) |
K59
![](../../../logos/mb/volmmc.gif)
|
![](../../../logos/mb/sockl.gif) 1
|
Remove relay (K59) from its socket.
Start engine.
HHT activation:
Stage 1
![](../../../logos/mb/ufdg.gif) ![](../../../logos/mb/uidg.gif) |
![](../../../logos/mb/uodg.gif)
11 - 14 V
|
Wiring,
7.2 |
7.2 |
Right front seat
Seat heater relay
(stage 1) (K59)
Activation |
B3
|
X55/4
![](../../../logos/mb/volmmc.gif)
|
![](../../../logos/mb/sockl.gif) B5
|
Disconnect X55/4 connector.
Start engine.
HHT activation:
Stage 1
![](../../../logos/mb/ufdg.gif) ![](../../../logos/mb/uidg.gif) |
![](../../../logos/mb/uodg.gif)
11 - 14 V
|
Wiring. |
8.0 |
Right front seat
Seat heater relay
(stage 2) (K59/1)
Function |
|
|
|
Replace seat heater relay (stage
2) (K59/1) with relay of same type i.e. with left seat heater relay
(K59/1).
Start engine.
HHT activation:
Stage 2
![](../../../logos/mb/ufdg.gif)
![](../../../logos/mb/ufdg.gif) ![](../../../logos/mb/foudg.gif) |
![](../../../logos/mb/uodg.gif)
Relay (K59/1) is activated.
![](../../../logos/mb/uodg.gif) ![](../../../logos/mb/ufdg.gif)
|
If the values are OK:
K59/1
If the values are not OK:
8.1 |
8.1 |
Right front seat
Seat heater relay
(stage 2) (K59/1)
Activation |
2 ![](../../../logos/mb/sockr.gif) |
K59/1
![](../../../logos/mb/volmmc.gif)
|
![](../../../logos/mb/sockl.gif) 1
|
Remove relay (K59/1) from its socket.
Start engine.
HHT activation:
Stage 2
![](../../../logos/mb/ufdg.gif) ![](../../../logos/mb/thrdg.gif) |
![](../../../logos/mb/uodg.gif)
11 - 14 V
|
Wiring,
8.2 |
8.2 |
Right front seat
Seat heater relay
(stage 2) (K59/1)
Activation |
B4
|
X55/4
![](../../../logos/mb/volmmc.gif)
|
![](../../../logos/mb/sockl.gif) B5
|
Disconnect X55/4 connector.
Start engine.
HHT activation:
Stage 2
![](../../../logos/mb/ufdg.gif) ![](../../../logos/mb/thrdg.gif) |
![](../../../logos/mb/uodg.gif)
11 - 14 V
|
Wiring. |
9.0 |
Right front seat heater switch
(S51/2)
Function |
![](../../../logos/mb/elgrou.gif) ![](../../../logos/mb/sockr.gif) |
|
N10
![](../../../logos/mb/sockl.gif) B11
(4)
|
Disconnect connect 4 at N10
Press switch (S51/2):
Heating stage 1
Heating stage 2 |
< 1
approx. 470
|
Wiring,
S51/2 |
10.0 |
Right front seat heater
Voltage supply |
B6 ![](../../../logos/mb/sockr.gif) |
X55/4
![](../../../logos/mb/volmmc.gif)
|
![](../../../logos/mb/sockl.gif) B5
|
Disconnect connect X55/4
Ignition: ON |
11 - 14 V
|
Wiring,
Convenience relay (F1k14) |
11.0 |
RF/RF seat cushion/backrest heater
element (R13/3, R13/4)
(stage 1)
Voltage supply
|
X54/9
B ![](../../../logos/mb/sockr.gif) |
|
X54/10
![](../../../logos/mb/sockl.gif) B
|
Disconnect connect X54/9 and X54/10
Start engine.
HHT activation
Stage 1
![](../../../logos/mb/ufdg.gif)
|
![](../../../logos/mb/uodg.gif)
11 - 14 V
|
Wiring. |
12.0 |
RF/RF seat cushion/backrest heater
element (R13/3, R13/4)
(stage 2)
Voltage supply
|
X54/9
B ![](../../../logos/mb/sockr.gif) |
|
X54/9
![](../../../logos/mb/sockl.gif) A
|
Start engine.
HHT activation:
Stage 2
![](../../../logos/mb/ufdg.gif)
|
![](../../../logos/mb/uodg.gif)
11 - 14 V
|
Wiring. |
13.0 |
RF seat cushion heater element
(R13/3)
Resistance |
X54/9
A ![](../../../logos/mb/sockr.gif) |
|
X54/9
![](../../../logos/mb/sockl.gif) B
|
Disconnect connector X54/9
|
5 - 10
|
Wiring,
R13/3 |
13.1 |
RF backrest heater element (R13/4)
Resistance |
X54/10
A ![](../../../logos/mb/sockr.gif) |
|
X54/10
![](../../../logos/mb/sockl.gif) B
|
Disconnect connector X54/10
|
5 - 10
|
Wiring,
R13/4 |