DIN 72552

Since quite a lot of traffic to this site is related to the meaning of automotive terminal designators, What is KLR, KL15, KL50, KL30, and KL31? and More about KL15, KL30, KL31, KL61, etc, it is probably worth my listing all the pins in the DIN 72552 standard.

DIN stands for “Deutsches Institut für Normung”, which in English translates to German Institute for Standardisation. Like the BSI in the UK or similar organisations, it is a member of ISO. Quite often, ‘DIN’ is incorrectly expanded as Deutsche Industrienorm (“German Industry Standard”).

DIN 72552 “Standard for labelling the electric terminals in automotive wiring” is a DIN standard for labelling the electric terminals in automotive wiring. The most frequently used labels are listed in the table below. Other standards are in use, but this is the one I primarily use1.

‘KL’ is the abbreviation for ‘klemme’, which is the German term for connector/connection, or ‘Klemmenbezeichnungen’. Klemmenbezeichnungen means Terminal designations.

Contact (KL code)MeaningOld Terminal designation
Ignition Systems
1ignition coil, distribution, low voltage
1a, 1bdistributor with two separate circuits
2breaker points magneto ignition
4coil, distributor, high voltage
4a, 4bdistributor with two separate circuits, high voltage
7terminal on ballast resistor, to distributor
15battery +VE from ignition switch16
15afrom the ballast resistor to the coil and starter motor16
15eBattery +VE from the ignition switch, also when the starter motor runs
Pre-Heat (Diesel engines)
15Pre-heat in+
17Start
19Pre-heat (Glow)
Starter
45Starter Relay30f, 30h
45aStarter 1 Output30h, 30h I
45bStarter 2 Output30h II
50Starter control
50aStarter control
50bStarter control50
50cStarter control50 II
50dStarter control50b, 50k
50eStarter control50a
50fStarter control50
50gStarter control50a
50hStarter control50
Battery
15Battery +VE through ignition switch16, 54/15
30Battery +VE direct230/51
30afrom 2nd battery and 12/24 V relay
31Return to battery -VE or direct to ground.
31areturn to battery -VE 12/24 V relay
31breturn to battery -VE or ground through switch85d
31creturn to battery -VE 12/24 V relay31, 31a
Electric motors
32Return31
33main terminal (swap of 32 and 33 is possible)30
33alimit
33bfeild54e
33f2. slow rpm
33g3. slow rpm
33h4. slow rpm
33Lrotation left30L
33Rrotation right30R
Indicators
49flasher unit in15, 15+. 15/54. +, +15, X
49aflasher unit out, indicator switch in54L, S, S4, L
49bOut 2. flasher circuit
49cOut 3. flasher circuit
C1st flasher indicator lightK, K1, P
C22nd flasher indicator lightK1, K2, K3, K4
C33rd flasher indicator lightK3, K4
Lindicator lights leftHL, L54, VL
Rindicator lights rightHR, R54, VR
L54Lights out, leftSBL
R54lights out, rightSB2
AC generator
51DC at rectifiers
51eAs 51, with choke coil
59AC out rectifier in, light switch51, 51-, 51a
59acharge, rotor out59
64generator control light
Generator – Voltage regulator
61charge indicator (charge control light)
B+Battery +VE51, 51B+, B+30, B+51
B-Battery -VE31B-
D+Dynamo/alterator diode +VE
D-Dynamo/alternator diode -VE
DFDynamo field
DF1Dynamo field 1
DF2Dynamo field 2
U, V, WAC three-phase terminals
Lights
54brake lights
54glights54
55fog lightsN
56spot light
56aheadlamp, high beam, and indicator light
56blow beamF
56dSignal flash
57Parking lights
57aParking lightsP
57Lparking lights leftPL
57Rparking lights rightPR
58licence plate lights, instrument panel
58dpanel light dimmer58b
58Lparking light
58Rparking light
Window wiper/washer
53wiper motor +VE in1, 3, 54d, S
53alimit stop +VE54, +2
53blimit stop field3, 54e
53cwasher pump
53estop field1, 2
53iwiper motor with permanent magnet, third brush for high speed
Acoustic warning
71beeper inH
71abeeper out, low
71bbeeper out, high
72hazard lights switch
85chazard sound on
Switches
81opener
81a1 out
81b2 out
82lock in
82a1st out
82b2nd out
82z1st in
82y2nd out
83multipositon switch in
83aout positon 1
83bout position 2
Relay
85relay coil -VEimportant if the relay coil has a built-in flyback diode in parallel
86relay coil +VE
Relay contacts
87common contact30/51
87anormally closed contact
87bnormally open contact
88common contact 230/51 (relay)
88anormally closed contact 2
88bnormally open contact 2
Additonal
52signal from trailer
54gmagnetic valves for trailer brakes
75radio, cigarette lighterR
77door valves control
DIN 72552 KL Table

Limitations of DIN 72552

One of the limitations of DIN 72552-2:2014-07 is that, since it was last updated over a decade ago, the prevalence of electric vehicles and the additional complexity due to the changes in a standard internal combustion engine vehicle mean that it no longer has enough detail to be used to describe the functions or wiring in its entirety. At this point, DIN 72552 tends to be limited to describing KL 15, KL 30 (and, by extension, KL 30_C), and KL 31. Beyond this, coding is best managed either as an extension of the PCB NET name or the function that the wire is attributed to.

KL coding and EVSE

EVSE equipment (Electric Vehicle Supply Equipment (yes, I know I added equipment twice)), does not have any KL coding for its pins. The OBC (On Board Charger) also doesn’t have KL coding. However, it does use Proximity Pilot and Control Pilot.

  1. EN 50005 – A different standard, European Norm (EN) 50005, recommends terminal numbering for general-purpose relays (e.g., 11/12/14/A1/A2 for a SPDT relay) that may nevertheless be applied to automobiles.
  2. KL30_C is the nonclamitature used by the company I work for to indicate the un-switched supply to contractors.

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