Relay Terminal Designations according to DIN 72552 Terminal Designation Terminal Designation 15 Switch-controlled plus downstream from battery Current relay (from ignition switch) 84 Input: Actuator and relay contacts 15a In-line resistor terminal leading to coil and 84a Output: Actuators starter Switching relay 30 Line from battery positive terminal (direct) 85 Output: Actuator (negative winding end or Series/parallel battery switch 12/24V ground) 30a Line from battery positive terminal II 86 Input: Actuator 31 Return line from battery negative terminal or 86a Start of winding ground (direct) Start of winding or first winding coil 31b Return line to battery negative terminal or Relay contact for NC and changeovers contacts ground via switch or relay (switch-controlled 87 Input ground) 87a First output (NC-contact side) 31a Battery changeover relay 12/24 V 87b Second output Return line to Battery II negative pole 87c Third output 48 Terminal on starter and start-repeating relay for 87z First input monitoring starting process 87y Second input Flasher relay (pulse generator) Relay contact for NO contact 49 Input 88 Input 49a 49b Output Relay contact for NO contact and changeover Output to second flasher relay contacts (NO side) Starter 88a First output 50 Starter control (direct) 88b Second output Battery switching relay Relay contact for NO contact 50a Output for starter control 88z First input Starter control 88y Second input 50b Dual starters in parallel operation with sequen- Generator/alternator and voltage regulator tial control B+ Battery positive terminal Starting relay for sequential control of en- B- Battery negative terminal gagement current for dual starters in parallel D+ Generator positive terminal 50c operation D- Generator negative terminal 50d Starter I input at starter relay DF Generator field winding Starter II input at starter relay DF1 Generator field winding 1 Start-locking relay Alternator 50e Input U, V, W Three-phase terminals 50f Output Turn signals (turn signal flasher) Start repeating relay C Indicator lamp 1 50g Input C0 Main terminal connection for indicator lamp not 50h Output connected to turn-signal flasher Trailer signalling devices C2 Indicator lamp 2 52 Supplementary signal transmission from trailer to C3 Indicator lamp 3 (eg for dual trailer operations) towing vehicle L Left-side turn signals Trailer signalling equipment 54 Trailer gladhand assembly and light combinations Stop lamps Switches, NC contacts and changeover contacts 81 Input 81a First output on NC-contact side 81b Second output on NC-contact side NO contacts 82 Input 82a First output 82b Second output 82z First input 82y Second input Multiple position swich 83 Input 83a Output (Pos.1) 83b Output (Pos. 2) 83L Output (Pos. left).