Over the years, I’veheard many explana-tions for why sometechnicians choose notto work on Europeanvehicles. For some, it’s

based on their desire to work only onvehicles built within our borders. Forothers, the choice may be based on thebelief that European cars are just too“foreign” and their systems too unusualor exotic to easily understand.

In today’s automotive economy, it hasbecome increasingly difficult to holdonto these attitudes. Many cars sold inthis country by European (and Asian)manufacturers are actually assembledright here in the U.S. This blurs theconventional definition of an importedvehicle. At the same time, many “Amer-ican” cars are actually assembled out-side our borders, further confusing theaccepted definition of a domestic car.

Auto manufacturing is truly a globalenterprise, with all of the major manu-facturers conducting business in sever-al countries simultaneously. Even if we

ignore the differences of language andculture, isn’t it still a difficult problemfor a European manufacturer to buildvehicles in a different country like theU.S.? To oversimplify the challengesinvolved, how do you get an Americanassembly line to crank out parts for aEuropean car? The answer is stan-dards. Standards have been an integralpart of the automotive world since theearliest days of the automotive assem-bly line. Standardization of parts al-lowed automakers to transform theirbusinesses from a one-at-a-time propo-sition to a many-at-a-time operation.

In this country, the Society of Auto-motive Engineers (SAE) is responsiblefor maintaining order by establishingmany of the standards that apply to au-tomobile manufacturing. When youpick a bolt for a domestic vehicle out ofthe bolt bin, chances are the standardsand specifications concerning itsthread pitch and hardness were origi-nally defined by SAE. Thanks to stan-dardization, that bolt should thread in-to any nut made anywhere in the

world, as long as it conforms to thesame set of standards.

In Europe, the most widely recog-nized organization responsible for es-tablishing and publishing automotivestandards is called Deutsches Institutfür Normung e.V. Standards estab-lished by this organization are often re-ferred to as DIN standards.

DIN standards have been estab-lished for a multitude of things, includ-ing many outside the automotiveworld, but we’ll limit the focus of this

38 April 2003

UnderstandingEuropeanDIN Wiring

BY KARL SEYFERT

European wiring diagrams may lookstrange and incomprehensible. But they’re

not so tough to understand when theunderlying standards are explained.

Fig. 1

article to the DIN standards for auto-motive wiring. Why wiring? Becausethat’s the one thing I’ve heard the mosttechs complain about when it comes toworking on European vehicles. Forsome, it’s the layout of the electricalcomponents throughout the vehicle.For others, it’s understanding thewiring diagrams that map out the posi-tion and operation of all those systemsand components. The diagrams maylook strange and incomprehensible.But when you understand the underly-ing system and standards that wereused to design the vehicles and the dia-grams, it’s not as tough as it first seems.

Terminal DesignationsDIN standard 72 552 establishes theterminal numbering system that’s usedfor any wiring diagram or vehiclewiring that conforms to DIN specifica-tions. The terminal codes are not wiredesignations, as devices with differingterminal codes can be connected tothe opposite ends of a single wire. Thechart on pages 42 and 43 outlines

many of the common terminal desig-nations described under DIN 72 552.Some of the more obscure numbers,which refer to components on trailers,heavy-duty trucks and such, have beenintentionally omitted.

When you’ve worked with DINwiring for a while, you’ll begin to recog-nize certain numbers that come intoplay more often than others. For exam-ple, a terminal 31 designation alwaysrefers to a direct connection to vehicleground and a terminal 30 designation

always represents a direct connection tothe battery positive terminal. And ter-minal 50 is always battery positive withthe key ON or in the CRANK position.

Wire Color CodesBefore we get into some actual DINwiring diagrams, a word about wirecolor codes. Most wiring diagramsyou’re likely to come across will havealready been translated into English.Wire colors in those diagrams shouldbe labeled with abbreviations you’ll beable to understand. But just in caseyou run across a diagram with the orig-inal wiring color codes, use the “WireColors” key at left to sort things out. Bythe way, color codes for electricalwiring are defined in DIN 47 002.

Circuit, Block &Schematic DiagramsDescription of an electrical system orcircuit may begin with a circuit dia-gram. This is an idealized representa-tion, rendered in the form of symbolsto provide a quick overview of circuit

39April 2003

WIRE COLORSEnglish DIN (German)Black . . . . . . . . . . . . . . . . . . . . .SwBlue . . . . . . . . . . . . . . . . . . . . . .BlBrown . . . . . . . . . . . . . . . . . . . .BrGreen . . . . . . . . . . . . . . . . . . . . .GnGray . . . . . . . . . . . . . . . . . . . . . .GrOrange . . . . . . . . . . . . . . . . . . .OrPink . . . . . . . . . . . . . . . . . . . . . .RsPurple . . . . . . . . . . . . . . . . . . . .ViRed . . . . . . . . . . . . . . . . . . . . . . .RtTurquoise . . . . . . . . . . . . . . . . . .TkWhite . . . . . . . . . . . . . . . . . . . . .WsYellow . . . . . . . . . . . . . . . . . . . .Ge

Fig. 3Fig. 2

and device functions. The circuit dia-gram illustrates the functional interre-lationships and physical links that con-nect various devices. These diagramsmay also include illustrations and sim-plified design drawings, as needed.

A block diagram is another simpli-fied representation of a circuit, showingonly the most significant elements. It’sdesigned to furnish a broad overview ofthe function, structure, layout and op-eration of an electrical system. This for-mat also serves as the initial referencefor understanding more detailedschematic diagrams. Squares, rectan-gles, circles and symbols illustrate thecomponents. Information about wirecolors, terminal numbers, connectors,etc., are omitted to keep the diagram assimple as possible.

The schematic diagram shows a cir-cuit and its elements in detail. Byclearly depicting individual currentpaths, it also indicates how the electri-cal circuit operates. Most DINschematic diagrams are current flowdiagrams. They’re arranged from topto bottom, so we can clearly see howthe current flows through the circuit.In a current flow diagram, a largeblock or several lines running acrossthe top represent the fuse/relay panel.This is the positive side of the circuit.The numbered line across the bottomrepresents the chassis ground, com-

pleting the circuit to the battery.Occasionally, a wire in a circuit will

be continued in another current track.When this happens, a small box with anumber inside will send you to the cur-rent track where the wire is continued.

Fig. 1 on page 38 is a schematic dia-gram of the gauge circuits on a Volkswa-gen. The lines across the top representthe positive feeds to the circuit. Thenumbers next to the bars define theirwire gauge size and color. The individ-ual gauges are mapped out in sequen-tial order below, making it very easy

to see how the current flows throughthe various sections of the circuit.

The diagram also includes informa-tion on terminal numbers, wire sizesand colors, connector sizes and a basicrepresentation of the internal workingof the gauges and sensors. The symbolsused to define the components alsoconform to DIN specifications. A keyexplaining these symbols will often beincluded with the schematic diagram.

Even if you’re fairly familiar with acircuit on a given car, a schematic dia-gram will help you find the correct lo-cation of a ground terminal, or helpyou identify a specific pin number in aconnector.

Another example of a current flowschematic diagram is shown in Fig. 2(page 39). This diagram also explainsthe meanings of some of the letters andnumbers in the diagram. The way thecomponents and wires are situated inrelation to one another in the diagramusually bears no resemblance to howthey’re actually arranged on the vehicle.

Break this diagram down and youcan see how it can work for you. Fourthings are needed to have a completecircuit: a source of power, wires or con-ductors of electricity, a load or a devicethat uses electricity and a ground. Theload needs both voltage and ground.The schematic tells you where theycome from, and where they need to go

40 April 2003

Understanding European DIN Wiring

Most DIN relays include a miniatureschematic diagram, right on the relayhousing. Flip the relay over and you’llf ind the relay terminals are alsonumbered. The numbers correspondto the DIN terminal designations.

The main fuse and relay panels on most European carscan be found under the hood. On older vehicles, like thisBMW, the panel is protected only by a plastic cover. Thepanels on more recent models do a better job of protect-ing fuses and relays from the elements.

Many older European vehicles are equipped with these bul-let-style fuses. The exposed fuse is wrapped around theends of the plastic or ceramic fuse body. The fuse is held inplace and makes electrical contact via the spring-loadedterminals at its ends. This fuse type can be the source of in-termittent electrical problems, especially in damp climates.

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to reach the load terminals. It also tellsyou which switching devices are usedto control the ON or OFF state of thecircuit. The schematic diagram is laidout so you can quickly find the parts ofa circuit and test them. For example:

•If there’s no power at the coolantthermo switch, the diagram shows thatfuse 1 is the source of power.

•If the fuse is good, the next step isto check the connections between thefuse and the thermo switch.

•The diagram shows two connec-tions—terminal 87 at the relay and pin6 of the green 10-point connector.Voltage testing at these points will helpyou determine where the break in thecircuit is located.

Let’s look at one more schematic dia-gram, this time the backup light circuitin Fig. 3 (page 39). Again, it’s a currentflow diagram, with all of the circuitcomponents laid out end to end. All ofthe wires, connectors and other compo-nents are clearly labeled and identified.At the bottom of the diagram, note thecircled numbers 7 and 8. These refer tothe actual locations of the ground con-nections indicated in the diagram. Anaccompanying vehicle diagram showsyou where the grounds are located.

The schematic diagrams used hereare admittedly on the basic side. Whenthe system involved is more complicat-ed, several circuits may be included inthe same diagram. Just remember,

these more complicated schematic dia-grams are assembled using the samebasic building blocks and DIN conven-tions found in the simpler diagrams.When you’re troubleshooting a specificcircuit problem, learn to home in onthe part of the circuit that’s involved,and tune out all the clutter around it. Ifnecessary, make a disposable copy ofthe diagram, then mark it up with col-ored pens or pencils until you under-stand how the circuit works.

DIN RelaysSuppose you’re diagnosing a relay in anelectrical circuit. Perhaps the wiring di-agram shows only a square box, with noinformation about what’s going on in-

42 April 2003

Understanding European DIN Wiring

1 . . . . . . . . . . .Ignition Coil, DistributorLow-Tension Circuit

Ignition Distributor With Two Insulated Circuits1a . . . . . . . . . .to Ignition Point Set I1b . . . . . . . . . .to Ignition Point Set II

Ignition Coil, Distributor4 . . . . . . . . . . . High-Tension Circuit

Ignition Distributor With Two Insulated Circuits4a . . . . . . . . . .Terminal 4, from Coil I4b . . . . . . . . . .Terminal 4, from Coil II

15 . . . . . . . . . .Switch-Controlled Positive Downstream from Battery(from Ignition Switch)

15a . . . . . . . . .In-Line Resistor Terminal Leading to Coil & Starter

Glow-Plug Switch17 . . . . . . . . . .Start19 . . . . . . . . . .Preglow

30 . . . . . . . . . .Line from Battery Positive Terminal (Direct)

31 . . . . . . . . . .Return Line from Battery Negative Terminalor Ground (Direct)

31b . . . . . . . . .Return Line to Battery Negative Terminal or Ground ViaSwitch or Relay (Switch-Controlled Ground)

Electric Motors32 . . . . . . . . . .Return Line*33 . . . . . . . . . .Main Connection*33a . . . . . . . . .Self-Parking Switch-Off33b . . . . . . . . .Shunt Field33f . . . . . . . . .for Reduced-RPM Operation, Speed 233g . . . . . . . . .for Reduced-RPM Operation, Speed 333h . . . . . . . . .for Reduced-RPM Operation, Speed 433L . . . . . . . . .Rotation to Left (Counterclockwise)33R . . . . . . . . .Rotation to Right (Clockwise)*Polarity Reversal of 32/32 Possible

Starter45 . . . . . . . . . .Separate Starter Relay, Output: Starter;

Input: Primary Current

Flasher Relay (Pulse Generator)51 . . . . . . . . . .Input49a . . . . . . . . .Output49b . . . . . . . . .Output to Second Flasher Relay49c . . . . . . . . .Output to Third Flasher Relay

Battery Switching Relay50a . . . . . . . . .Output for Starter Control

Start-Locking Relay50e . . . . . . . . .Input50f . . . . . . . . .Output

Start-Repeating Relay50g . . . . . . . . .Input50h . . . . . . . . .Output

AC Generator (Alternator)51 . . . . . . . . . .DC Voltage at Rectifier51e . . . . . . . . .DC Voltage at Rectifier with Choke Coil

for Daylight Operation

Starter52 . . . . . . . . . .Starter Control (Direct)

53 . . . . . . . . . .Wiper Motor, Input (+)53a . . . . . . . . .Wiper (+), End Position53b . . . . . . . . .Wiper (Shunt Winding)53c . . . . . . . . .Electric Windshield Washer Pump53e . . . . . . . . .Wiper (Brake Winding)53i . . . . . . . . .Wiper Motor with Permanent Magnet & Third Brush

(for Higher Speed)

55 . . . . . . . . . .Front Fog Lamp

56 . . . . . . . . . .Headlights56a . . . . . . . . .High Beam with Indicator Lamp56b . . . . . . . . .Low Beam56d . . . . . . . . .Headlight Flasher Contact

57 . . . . . . . . . .Parking Lamps (in some export markets)57a . . . . . . . . .Parking Lamps57L . . . . . . . . .Parking Lamps, Left57R . . . . . . . . .Parking Lamps, Right

WIRING TERMINAL DESIGNATIONSTerminal Definition Terminal Definition

side the relay. Or maybe you need tobench-test the relay or jumper the con-nector but can’t see the wire colors. Ifthe vehicle uses DIN standards, the re-lay will provide you with informationabout its inner workings, just by lookingat its terminal numbers. And for a morethorough explanation, many DIN re-lays even include a tiny schematic dia-gram on the outside of the housing.

Relays are electrically controlledswitches. The switch inside the relaywill be in one of two positions, de-pending on whether the electromag-netic relay coil is energized or deener-gized. In basic relays, there’s one inputand either one or two outputs. Relaysare either normally open (NO) or nor-

mally closed (NC). In either case, therelay switch input is always connectedto pin 30. Pin 30 not only designatesthe input to the relay switch, but in ac-cordance with DIN standards, we alsoknow that it’s connected to battery pos-itive. The relay outputs on the otherside of the relay switch are designatedeither 87, 87a or 87b.

The two remaining relay terminalsare connected to the relay coil. Apply-ing current to the coil is what makes therelay close or open. According to DINstandards, pin 85 should be connectedto ground (usually controlled by anotherswitch) and pin 86 should be connectedto battery positive (usually protected bya fuse). This one is not a hard and fast

rule, apparently, as you may encounterrelays where the polarities of terminals85 and 86 have been reversed.

How does DIN pin number informa-tion help in the real world? By using pininformation, you may be able to reducethe amount of time spent with locatormanuals. When you remove a relay orlook at a connector, you should be ableto figure out how it works just by look-ing at the pin assignments.

43April 2003

Visit www.motor.com todownload a free copy of this

article. Copies are also availableby sending $3 for each copy to:

Fulfillment Dept., MOTOR Magazine,5600 Crooks Rd., Troy, MI 48098.

58 . . . . . . . . . .Side-Marker Lamps, Taillamps, License Plate& Instrument Illumination

58d . . . . . . . . .Rheostatic Instrument Illumination, Tail- & Side-Marker Lamps58L . . . . . . . . .Left58R . . . . . . . . .Right, License Plate Lamps

AC Generator (Alternator)(Magneto Generator)59 . . . . . . . . . .AC Voltage Output, Rectifier Input59a . . . . . . . . .Charging-Armature Output59b . . . . . . . . .Taillamp Armature, Output59c . . . . . . . . .Stop-Lamp Armature, Output

61 . . . . . . . . . .Charge Indicator Lamp

Tone-Sequence Controller71 . . . . . . . . . .Input71a . . . . . . . . .Output to Horns I & II (Bass)71b . . . . . . . . .Output to Horns 1 & 2 (Treble)

75 . . . . . . . . . .Radio, Cigarette Lighter

76 . . . . . . . . . .Speakers

77 . . . . . . . . . .Door Valve Control

Switches, Normally Closed (NC) Contacts & Changeover Contacts81 . . . . . . . . . .Input81a . . . . . . . . .First Output on NC-Contact Side81b . . . . . . . . .Second Output on NC-Contact Side (NO Contacts)82 . . . . . . . . . .Input82a . . . . . . . . .First Output82b . . . . . . . . .Second Output82z . . . . . . . . .First Input82y . . . . . . . . .Second Input

Multiple-Position Switch83 . . . . . . . . . .Input83a . . . . . . . . .Output (Pos. 1)83b . . . . . . . . .Output (Pos. 2)83L . . . . . . . . .Output (Left)83R . . . . . . . . .Output (Right)

Current Relay84 . . . . . . . . . .Input: Actuator & Relay Contacts84a . . . . . . . . .Output: Actuators84b . . . . . . . . .Output: Relay Contacts

Switching Relay85 . . . . . . . . . .Output: Actuator (Negative Winding End or Ground)

Input: Actuator86 . . . . . . . . . .Start of Winding86a . . . . . . . . .Start of Winding or First Winding Coil86b . . . . . . . . .Winding Tap or Second Winding Coil

Normally Closed (NC) Relay Contact & Changeover Contacts87 . . . . . . . . . .Input87a . . . . . . . . .First Output (NC-Contact Side)87b . . . . . . . . .Second Output87c . . . . . . . . .Third Output87z . . . . . . . . .First Input87y . . . . . . . . .Second Input87x . . . . . . . . .Third Input

Normally Open (NO) Relay Contact88 . . . . . . . . . .Input88z . . . . . . . . .First Input88y . . . . . . . . .Second Input88x . . . . . . . . .Third Input

Normally Open (NO) Relay Contact & Changeover Contacts (NO Side)88a . . . . . . . . .First Output88b . . . . . . . . .Second Output88c . . . . . . . . .Third Output

Generator/Alternator & Voltage RegulatorB� . . . . . . . . .Battery Positive TerminalB� . . . . . . . . .Battery Negative TerminalD� . . . . . . . . .Generator Positive TerminalC� . . . . . . . . .Generator Negative TerminalDF . . . . . . . . . .Generator Field WindingDF1 . . . . . . . . .Generator Field Winding 1DF2 . . . . . . . . .Generator Field Winding 2

AlternatorU, V, W . . . . . .Three-Phase Terminals

Turn Signals (Turn-Signal Flasher)C . . . . . . . . . . .Indicator Lamp 1C0 . . . . . . . . . .Main Terminal Connection for Indicator Lamp Not

Connected to Turn-Signal FlasherC2 . . . . . . . . . .Indicator Lamp 2L . . . . . . . . . . .Left-Side Turn SignalsR . . . . . . . . . . .Right-Side Turn Signals

Terminal Definition Terminal Definition