Engine bay electrical centre 342 (UEC)

 Location

The electrical centre is located between the battery and the left front wing.

 Main task

Act as the electrical centre for the front of the car and handle some parts of the logic for the front lighting as well as the visibility and signal systems.

Distributes current from the battery to the other electrical centres.

The electrical centre contains the transport fuse (fuse 37).

 Type

Electrical centre with relays, maxi and micro-fuses and integrated control module for logic operations.

 Connect

The fuse box is connected to the battery and to grounding points G30A, G31 and G33S. The electrical centre is connected via three switches in its base to the engine harness, front harness and main harness.

Power supply circuit for +30

Power supply circuit for +15

The engine harness is connected via switch M

M (engine harness)

Pin Component/Function In/Out
1

Petrol: P-bus

Diesel: A/C compressor

In/Out

Out

2

Petrol: Not connected

Diesel: P-bus



In/Out

3

Not connected



4

Radiator fan 3

In

5

Radiator fan 2

In

6

Z18XE: A/C compressor

Diesel: Main relay (coil)

Out

7

Not connected



8

ECM



9

Switch, reverse gear



10

Radiator fan 1



11

Petrol: Not connected

Diesel: Relay, preheating



Out

12

Not connected



13

Not connected



14

Simtec: Fuel pump

Diesel: Glow plug control module; fuel pump

Out

15

Main relay

Out

16

Control module, glow plug

Out

17

Start relay



18

Not connected



19

Not connected



20

Not connected



21

ECM (starting control)



22

TCM (starting control)



23

Z18E: Main relay

Diesel: Relay, preheating

In

24

ECM



25

TCM



26

Z18XE + Z19: A/C relay



27

Clutch switch

In

28

ECM (starting control)



29

Not connected



30

P-Bus

In/Out



The front harness is connected via switch F

F (front harness)

Pin Component/Function In/Out
1

Parking light, right, front

Out

2

Direction indicator, right, front

Out

3

Direction indicator, left, front



4

Side direction indicator, left, front



5

Side marker lamp, right



6

Side marker lamp, left



7

Not connected



8

Parking light, left, front



9

Side direction indicator, right, front



10

Fog light, right, front



11

Wipers, front, park position



12

Not connected



13

Not connected



14

Washer fluid, level sensor



15

Not connected



16

Dipped beam, right



17

Main beam, left



18

Parking heater

Out

19

Level control, headlamps

Out

20

Radiator fan, low-speed

Out

21

Main beam, right



22

Pump, headlamp washer



23

Not connected



24

Radiator fan, high-speed

Out

25

Dipped beam, left



26

Power ground



27

Power ground



28

Not connected



29

Windscreen wiper motor, high-speed



30

Windscreen wiper motor, low-speed



31

Not connected



32

Not connected



33

Fog light, left, front



34

Horn



35

Auxiliary lamp



36

Pump, windscreen washer



37

I-bus



38

Not connected



39

Not connected



40

Not connected



41

Not connected



42

Not connected



43

Pump, rear window washer



44

P-Bus



45

P-Bus



46

Not connected



47

Radiator fan 3



48

Radiator fan 2



49

Radiator fan 1



50

I-bus





The main harness is connected via switch B

B (main wiring harness)

Pin Component/Function In/Out
1

+15 feed

Out

2

I-bus



3

I-bus



4

Clutch switch



5

Battery disconnect

Out

6

P-Bus



7

Not connected



8

+30 supply 2 to REC

Out

9

+30 feed to TCS/ESP

Out

10

Not connected

Out

11

+30 supply 2 to IPBEC

Out

12

+30 supply 3 to REC

Out

13

+30 supply 1 to IPBEC

Out

14

+30 supply amplifier for front speakers

Out

15

+30 supply 1 to REC

Out

16

+30 feed logic to TCS/ESP

Out

17

P-Bus



18

Electronic ground



19

Brake/clutch switch



20

+15 supply to TCM/TRS

Out

21

I-bus



22

I-bus





 Fuses

The electrical centre can contain a greater number of fuses than those listed below. In such cases, these are not connected to a wiring harness.

No. Amp Type Function Illustration
1

30

+30

EDC16 via main relay 229:

ECD16 control module (595B)

Glow plug control module (596)

Boost pressure control valve (179a)

Actuator, swirl throttle (403)

Solenoid valve, EGR (603)

Actuator, throttle body (604)

Simtec via main relay 229:

Control module, Simtec (705)

Heated oxygen sensors (271)

EVAP canister purge valve (321)

Control valve, VIM damper (454)

Module, mass air flow sensor (686)



2

10

+30

TCM (502)

Trionic T8 control module (589A)

Simtec control module (705B)



3

20

+30

Horn



4

10

+15

T8:

Trionic T8 control module (589A)

Simtec:

Simtec control module (705B)

Module, ignition coils (552)

Module, power steering unit (745)

EDC16:

ECD16 control module (595B)

TCM, AF 40 (502b)

Module, mass air flow sensor (686)

Water level sensor, fuel filter (692)

Module, power steering unit (745)



5

--



--



6

10

+30

TCM, FA 57 (502a)

Immobilizer switch, automatic (77)

Gear selector, automatic (245)

Immobilizer switch (411)



7





--



8





--



9





--



10





--



11





--



12





--



13

10

+30

EDC16 and Simtec: A/C compressor (170)



14





--



15

30

+30

Motor, high-pressure headlight washer pump (668)



16

30



Lighting, left front:

Side direction indicators, dipped beam, fog light

Lighting, right front:

Position lamp, direction indicator, side direction indicator, main beam



17

30



Windscreen wiper motor, low-speed



18

30



Windscreen wiper motor, high-speed



19

20

+30

Parking heater, diesel (597)

Connection, accessories (711)



20

10

+15

Motors, manual headlamp levelling (280)

AHL control module (664)



21





--



22

30

+30

Washer fluid pump, windscreen



23





--



24

20

+30

Auxiliary lamp



25

20

+30

Front amplifier



26

30

+30

Lighting, left front:

direction indicator, position lamp, main beam

Lighting, right front:

dipped beam, fog light



27

60

maxi

20

maxi

+30

T8:

Electrical centre 727

Simtec and EDC16:

fuel pump (323)







28

40

maxi

+30

TCS/ESP



29

60

maxi

+30

Main fuse 2 for rear electrical centre



30

60

maxi

+30

Main fuse 2 for dashboard electrical centre



31

40

maxi

+30

Starter motor solenoid via relay 517



32

60

maxi

+30

Main fuse 1 for dashboard electrical centre



33

40

maxi

+30

TCS/ESP



34

60

maxi

+30

Main fuse 1 for rear electrical centre



35

30

maxi

+30

B207 and Z18XE: Radiator fan



36

20

maxi

+30

B207: Radiator fan

EDC16: Heating element, fuel filter



37

60

maxi

+30

Transport lock. Main fuse 3 for rear electrical centre





 Relays

The electrical centre can contain a greater number of relays than those listed below. In such cases, these are not connected to a wiring harness.

Location No. Description Illustration Diagram
R1

432b

Relay, washer fluid pump, windscreen





R2

156

Relay, A/C compressor (Simtec and EDC16)



Simtec

EDC16

R3



--



 
R4

641

Relay, diesel preheating





R5

675

Relay, extra lights





R6

68

Horn relay





R7

229

Main relay, engine management system (Simtec and EDC16)





R8

517

Relay, +50



AUT

MAN

diesel

R9

83

Windscreen wiper relay





R10



--



 
R11

757F

Relay, +15, UEC





R12

709

Relay, windscreen wiper, full/half speed





R13



--



 
R14

667

Relay, washer fluid pump, high-pressure, headlamp





R15



--



 
R16



--