Central locking (except Japan) – circuit operation
- Make
- Land Rover
- Model
- Discovery Electrical Troubleshooting Manual
- Year
- 1997 on
- Section
- Circuit operation › Central locking (except Japan) – circuit operation
CENTRAL LOCKING (EXCEPT JAPAN) – CIRCUIT OPERATION
CIRCUIT OPERATION
The locking functions on models with the Theft Alarm System are controlled by the Theft Alarm Unit (2163). Refer to the Theft Alarm System (T1). The locking functions on models without the Theft Alarm System are controlled by the Right Front Door Lock Actuator (M122).
The four doors and the tailgate are locked or unlocked using the right front exterior key or the interior door sill knob. The rear doors can be independently locked or unlocked from the inside by using the appropriate door sill knob. These can be overridden when the lock controls in the right front door are used. The left front door and the rear doors may be locked or unlocked in isolation from the outside using the key or from the inside using the door sill knob.
Lock
When the doors are locked by the right front exterior key or the interior door sill knob, the internal microswitches in the Right Front Door Lock Actuator (M122) move to the “Lock” position. Voltage from fuse F4 is applied to the lock actuators through the K wires. The lock actuators are grounded at E200 through the microswitch contacts and the O wires. The doors and the tailgate now lock. The solid state load sensor/timer ensures that the motors operate only for the time required to lock or unlock the doors and the tailgate.
Unlock
When the doors are unlocked by the right front exterior key or the interior door sill knob, the internal microswitches in the Right Front Door Lock Actuator (M122) move to the “Unlock” position. Voltage from Fuse F4 is applied to the lock actuators through the O wires. The lock actuators are grounded at E200 through the microswitch contacts and the K wires. Since the polarity of the voltage is now reversed, the doors and the tailgate unlock.
CIRCUIT OPERATION 1
Parts & tools for this job For 1997 Land Rover Discovery
- TOOLDigital multimeterSearch: automotive digital multimeter
- PARTAssorted fuse kitSearch: car fuse assortment kit
- TOOLWire crimper and connector kitSearch: wire crimper connector kit
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