All about U1

Connections

High-voltage connection

Depending on the angle at which it is viewed, this connection is the end of the secondary coil or the connection point to the distributor and/or spark plug. Through this connection, the ignition voltage travels to the distributor and from there via the individual ignition wires to the spark plugs, where a spark-over occurs.

Terminals 1 and 15

Low-voltage connections: minus / ignition signal / Trigger(1) and battery power / 12V (15) terminals. The ignition coil is supplied with current through these terminals.

Block coils

Block coils (some with integrated ignition module) like U1001 often combine the low voltage connections in a compact connector. (Pin assignment: Battery voltage, ground (GND), ignition signal (Trig) from engine control module)