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General Electrical System - Service Techniques (E88): Overview BMW 1 series F20/F21

Horns 2 illustrations ~1327 words

Scheme 563

Scheme 563: Glossary Of Electrical Components: All models from E38 and MINI

Alphanumerical overview of abbreviated designations

Abbreviated designations are alphabetically sorted in the following groups

  1. A Control units, modules
  2. B Sensors, electric converters
  3. D Diagnosis interfaces
  4. E Lights, electric heating equipment
  5. F Fuses
  6. G Power supply, gas generators
  7. H Acoustic and visual warning systems
  8. I Components from BMW suppliers
  9. K Relays
  10. L Coils
  11. M Electric motors, drives
  12. N Amplifiers, regulators, control units
  13. P Display instruments
  14. R Resistors, potentiometers
  15. S Switches, buttons
  16. T Ignition coils
  17. U Radio systems, suppressor filters
  18. V Semiconductors, diodes
  19. W Aerials, screening
  20. X Connectors
  21. Y Electromechanical components
  22. Z Blocking circuits, suppressor filters

Subject to change.

Scheme 564

Scheme 564: Interior mirror with digital compass : E70, E71, E82, E83, E88, E90, E91, E92, E93

Brief description of components

The following components deliver signals for the digital compass

  1. Magnetic field sensor
  1. up to 09/2006

The magnetic field sensor is installed in the mirror base. The magnetic field sensor measures the current alignment of the magnetic field. The signal is sent to the control electronics for the compass in the interior mirror.

  1. from 09/2006

The magnetic field sensor is on the PCB in the interior mirror.

  1. Control electronics for the compass

The interior mirror is electrically connected to the roof control panel (FZD).

The control electronics for the compass are integrated into the board for the interior mirror. The signals from the magnetic field sensor are received by the control electronics. The LCD display is activated directly by the control electronics.

The following components are controlled

  1. Display in interior mirror
  1. up to 09/2006

The LC display (window) is situated at top right in the interior mirror.

The points of the compass are presented digitally on the LCD display (LCD: Liquid Crystal Display). The display is divided into eight compass points.

  1. from 09/2006

The point of the compass is displayed in transparent light technology in the interior mirror as well. The display is also at the top right in the interior mirror. The display is divided into eight compass points.

The junction box consists of the distribution box and the junction box electronics.

  1. JBE: Junction box electronics The junction box electronics unit combines numerous functions in a single control unit. The junction box electronics unit is connected via 4 plug connections. A 54-pin connector connects the instrument panel. Two further connectors are for the connection on the main wiring harness. These connectors are 54-pin and 47-pin. A 23-pin internal connection directly connects the junction box electronics to the power distributor.
  2. Electrical distributors The fuses and various plug-in relays are located in the junction box distribution box. The boards in the distribution box are connected to various relays, depending on the equipment specification. There is an opening in the lower section of the junction box. The junction box electronics unit is connected with the distribution box through this opening.

Note. For current details about the pin assignment and fuse assignment of the junction box electronics and the power distributor, please refer to appropriate WIRING DIAGRAM article. Different versions of the power distributor are fitted, depending on the model series and Model Year measures. For example, the complete fuse assignment may change as part of Model Year measures. 03/2007 Model Year measure (not E70, E71): primarily changes to pin assignment 09/2007 Model Year measure (not E70, E71): primarily changes to fuse assignment Depending on the vehicle equipment, various relays are mounted on the boards in the power distributor.

The following components are involved in the power supply

  1. Alternator The alternator generates the charge voltage for the battery and the power supply for the consumers. The alternator generates a variable voltage, depending on the engine speed (alternator voltage). The power management system regulates this variable voltage.
  2. Battery The vehicle battery is fitted inside a plastic casing in the luggage compartment. The capacity of the battery installed depends on the engine used and the equipment installed in the vehicle.
  3. Junction box The junction box is fitted behind the glove box underneath the instrument panel. The junction box consists of a power distributor and a control unit, the junction box electronics (JBE, see below). The power distributor holds fuses and relays. The following relays are of particular importance for the power supply: Terminal 15 relay Terminal 30g relay for consumer cutoff (see below under " «SYSTEM FUNCTIONS»(ref-351560-S19234842962009122200000) ") Terminal 30g-f relay for cutoff in case of fault (see below under " «SYSTEM FUNCTIONS»(ref-351560-S19234842962009122200000) ") NOTE: For current details about the pin assignment and fuse assignment of the junction box electronics and the power distributor, please refer to appropriate WIRING DIAGRAMS article. Different versions of the power distributor are fitted, depending on the model series and Model Year measures. For example, the complete fuse assignment may change as part of Model Year measures. 03/2007 Model Year change: primarily changes to pin assignment 09/2007 Model Year change: primarily changes to fuse assignment Depending on the vehicle equipment, various relays are mounted on the boards in the power distributor.
  4. Front and rear power distributors The BMW 1-Series and the BMW 3-Series have the following power distributors: Power distributor in the engine compartment: Electronics box Power distributor in the luggage compartment: Rear fuse block The fuse block is secured to the vehicle battery by a retaining clip. The fuse block can only be replaced as a complete unit. Fuses cannot be replaced individually. The fuse block holds the fuses for the following consumers: Valvetronic Common rail (fuel injection on diesel) Electric auxiliary heater Power distributor in junction box
  5. Intelligent battery sensor Only on vehicles with High equipment level, e.g. CCC or M-ASK (CCC: Car Communication Computer, M-ASK: Multiaudio system controller) The intelligent battery sensor evaluates the current quality of the battery. The intelligent battery sensor is a part of the battery negative terminal. The intelligent battery sensor regularly (cyclically) measures the following values: Battery voltage Charge current Discharge current Battery temperature The following control units are involved in the power supply
  6. JBE: Junction box electronics The JBE is the control unit in the junction box. The JBE is the central data interface in the vehicle (gateway for the bus systems).
  7. CAS: Car Access System The Car Access System is involved in the terminal control (terminal R, terminal 15, terminal 30g). The terminal control supplies important messages for the power supply. The CAS is connected to the following components and control units: The Car Access System is connected by a direct wire to the START/STOP button and to the slot for the ID transmitter. The START/STOP button and the slot are located next to the steering column. The starter motor and the DME/DDE are connected to the CAS. The CAS control unit is a bus subscriber on the K-CAN.
  8. DME: Digital engine electronics or DDE: Digital diesel electronics The DME/DDE influences the power supply as follows: If the alternator voltage drops, the DME/DDE will increase the engine speed as needed. The software for this is called "power management". The DME/DDE is connected to the PT-CAN (Powertrain Controller Area Network) as part of the bus system. If an intelligent battery sensor is fitted, the DME/DDE will evaluate the current battery condition. In this way, the DME/DDE also influences terminal 30g-f (see below under " «SYSTEM FUNCTIONS»(ref-351560-S19234842962009122200000) ").
  9. MRS: Multiple restraint system The MRS control unit interrupts the power supply as follows if an accident exceeding a certain severity occurs: The safety battery terminal is separated from the battery. The electric fuel pump is switched off. The following data buses and wires are important for the power supply
  10. Bitserial data interface The bitserial data interface is the data connection between the engine control unit (DME/DDE) and the alternator.
  11. 2 battery cables 2 battery cables connect the battery to the engine compartment: One of the battery cables runs via the jump-start connection point to the starter and alternator. The other cable is used for the voltage supply for the fuel injection system (on spark-ignition engines: Valvetronic, on diesel engines: Common rail system). Both battery cables are routed on the vehicle underbody on the BMW 1-Series and BMW 3-Series.