Circuit/System Description

The door open switch and the door ajar switch contacts will be open when the door is fully closed, the door switches within the door latch are designed so that the when the door is ajar, the contact in the door ajar switch closes, the voltage is pulled low and the window motor will then send a serial data message to the body control module indicating that the door is ajar. When the door is opened further, the contact in the door open switch will then decrease the resistance in the signal circuit to the ground for the door open signal circuit, the body control module will then determine from the change in the voltage level that the door is open.

The K9 Body Control Module supplies the A23D Front Side Door Latch-Driver a 5 V Reference through the open switch signal circuit 126. The A23D Front Side Door Latch-Driver contains a multiplexed resistor. When the driver door is closed the open switch contacts will be open, when the door is open the contacts in the switch will close which will decrease the resistance between signal circuit 126 and ground. The body control module will then determine from the change in the voltage level that the door is open.

The M74D Front Side Door Window Regulator Motor-Driver provides the A23D Front Side Door Latch-Driver 12 V through the door ajar signal circuit 745. Ground is applied at all times to the A23D Front Side Door Latch-Driver. When the driver door is closed the ajar switch contacts will be open, when the driver door is ajar the contacts in the switch will close providing ground to signal circuit 745. M74D Front Side Door Window Regulator Motor-Driver will then send a serial data message to the body control module indicating that the door is ajar.