Closed-circuit (standby) current cut-out

The electrical closed circuit cut-out function switches off loads which consume closed circuit (standby) current at terminal 30. The closed circuit current cut-out is controlled by the load cut-out relay K72.

A voltage filter is also integrated in the relay K72 to filter the ripple of the electrical system. This filter is necessary for the motors of the steering column and seat memory.

The following systems are connected to the closed circuit current cut-out:

• 7 series, E38, up to model year 1996: Seat adjustment, rear head restraint adjustment, steering column adjustment and sun shade.
  
• 7 series, E38, as of model year 1996: Seat/steering column memory
  
• 5 Series, E39: Seat/steering column memory
  

The relay K72 is driven via terminal 15 and the "load cut-out" signal from the basic module of the ZKE III

Load cut-out signal

The load cut-out signal is switched by the basic module of the ZKE III.

When terminal R is switched on, B+ is switched from the basic module to the relay K72. The basic module switches off the B+ supply 16 minutes after switching off terminal R.

The relay is switched on again together with switching on terminal R or terminal 15 or, when a signal change takes place at an input of the ZKE III; e.g. opening a door, opening the front lid, unlocking a door.

When terminal 15 is switched on (signal at Pin 8 of relay K72) the closed circuit current cut-out relay switches on the B+ supply for the connected loads irrespective of the status of the load cut-out signal.