DIN 72552 is a DIN standard for automobile electric terminal numbers, standardizing almost every contact in an automobile with a number code.
This table gives most frequently used numbers.
EN 50005
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.
References
DIN 72552 Wikipedia(Text) CC BY-SA