DIN 72552 is a DIN standard for labeling the electric terminals in automotive wiring. The most frequently used labels are listed in the table below.
| Contact | Meaning | Old terminal designation[1] |
|---|---|---|
| Ignition system | ||
| 1 | ignition coil, distributor, low voltage | |
| 1a, 1b | distributor with two separate circuits | |
| 2 | breaker points magneto ignition | |
| 4 | coil, distributor, high voltage | |
| 4a, 4b | distributor with two separate circuits, high voltage | |
| 7 | terminal on ballast resistor, to distributor | |
| 15 | battery+ from ignition switch | 16 |
| 15a | from ballast resistor to coil and starter motor | 16 |
| 15e | battery+ from ignition switch, also when starter motor runs | |
| Preheat (Diesel engines) | ||
| 15 | preheat in | + |
| 17 | start | |
| 19 | preheat (glow) | |
| Starter | ||
| 45 | starter relay | 30f, 30h |
| 45a | starter 1 output | 30h, 30h I |
| 45b | starter 2 output | 30h II |
| 50 | starter control | |
| 50a | starter control | |
| 50b | starter control | 50 |
| 50c | starter control | 50 II |
| 50d | starter control | 50b, 50k |
| 50e | starter control | 50a |
| 50f | starter control | 50 |
| 50g | starter control | 50a |
| 50h | starter control | 50 |
| Battery | ||
| 15 | battery+ through ignition switch | 16, 54/15 |
| 30 | from battery+ direct | 30/51 |
| 30a | from 2nd battery and 12/24 V relay | |
| 31 | return to battery- or direct to ground | |
| 31a | return to battery- 12/24 V relay | |
| 31b | return to battery- or ground through switch | 85d |
| 31c | return to battery- 12/24 V relay | 31, 31a |
| Electric motors | ||
| 32 | return | 31 |
| 33 | main terminal (swap of 32 and 33 is possible) | 30 |
| 33a | limit | |
| 33b | field | 54e |
| 33f | 2. slow rpm | |
| 33g | 3. slow rpm | |
| 33h | 4. slow rpm | |
| 33L | rotation left | 30L |
| 33R | rotation right | 30R |
| Indicators | ||
| 49 | flasher unit in | 15, 15+, 15/54, +, +15, X |
| 49a | flasher unit out, indicator switch in | 54L, S, S4, L |
| 49b | out 2. flasher circuit | |
| 49c | out 3. flasher circuit | |
| C | 1st flasher indicator light | K, K1, P |
| C2 | 2nd flasher indicator light | K1, K2, K3, K4 |
| C3 | 3rd flasher indicator light | K3, K4 |
| L | indicator lights left | HL, L54, VL |
| R | indicator lights right | HR, R54, VR |
| L54 | lights out, left | SBL |
| R54 | lights out, right | SBR |
| AC generator | ||
| 51 | DC at rectifiers | |
| 51e | as 51, with choke coil | |
| 59 | AC out, rectifier in, light switch | 51, 51-, 51a |
| 59a | charge, rotor out | 59 |
| 64 | generator control light | |
| Generator, voltage regulator | ||
| 61 | charge indicator (charge control light) | |
| B+ | battery + | 51, 51B+, B+30, B+51 |
| B- | battery - | 31B- |
| D+ | dynamo/alternator diode+ | |
| D- | dynamo/alternator diode- | |
| DF | dynamo field | |
| DF1 | dynamo field 1 | |
| DF2 | dynamo field 2 | |
| U, V, W | AC three phase terminals | |
| Lights | ||
| 54 | brake lights | |
| 54g | lights | 54 |
| 55 | fog light | N |
| 56 | spot light | |
| 56a | headlamp high beam and indicator light | |
| 56b | low beam | F |
| 56d | signal flash | |
| 57 | parking lights | |
| 57a | parking lights | P |
| 57L | parking lights left | PL |
| 57R | parking lights right | PR |
| 58 | licence plate lights, instrument panel | |
| 58d | panel light dimmer | 58b |
| 58L | parking light | 58 |
| 58R | parking light | 58 |
| Window wiper/washer | ||
| 53 | wiper motor + in | 1, 3, 54d, S |
| 53a | limit stop + | 54, +2 |
| 53b | limit stop field | 3, 54e |
| 53c | washer pump | |
| 53e | stop field | 1, 2 |
| 53i | wiper motor with permanent magnet, third brush for high speed | |
| Acoustic warning | ||
| 71 | beeper in | H |
| 71a | beeper out, low | |
| 71b | beeper out, high | |
| 72 | hazard lights switch | |
| 85c | hazard sound on | |
| Switches | ||
| 81 | opener | |
| 81a | 1 out | |
| 81b | 2 out | |
| 82 | lock in | |
| 82a | 1st out | |
| 82b | 2nd out | |
| 82z | 1st in | |
| 82y | 2nd in | |
| 83 | multi position switch, in | |
| 83a | out position 1 | |
| 83b | out position 2 | |
| Relay | ||
| 85 | relay coil - | Important if relay coil has flyback diode in parallel |
| 86 | relay coil + | Important if relay coil has diode in parallel |
| Relay contacts | ||
| 87 | common contact | 30/51 |
| 87a | normally closed contact | |
| 87b | normally open contact | |
| 88 | common contact 2 | 30/51 (relay) |
| 88a | normally closed contact 2 | |
| 88b | normally open contact 2 | |
| Additional | ||
| 52 | signal from trailer | |
| 54g | magnetic valves for trailer brakes | |
| 75 | radio, cigarette lighter | R |
| 77 | door valves control | |
A different standard, European Norm (EN) 50005 recommends terminal numbering for general application relays (e.g. 11/12/14/A1/A2 for a SPDT relay) that may nevertheless be applied to automobiles.