Workshop Manuals Factory service & repair Land Rover
01 Introduction02 Multiport fuel injection (MFI-V8)03 Multiport fuel injection (MFI-T16)04 300Tdi05 300Tdi glow plug control06 Starting and charging07 Cruise control08 Ignition and shift interlock09 Anti-lock brake system10 Data link connector11 Instruments12 Warnings and indicators13 Horns14 Radio (EXCEPT Japan)15 Radio (Japan)16 Radio (NAS)17 Front wipe/wash18 Rear wipe/wash19 Heated front screen20 Heated rear screen and mirror demisters21 Electrochromic rear view mirror22 Multi-function unit (MFU)23 Headlamps (EXCEPT Japan)24 Headlamps (Japan)25 Headlamp levelling26 Side lamps27 Stop lamps28 Direction indicator lamps29 Reversing lamps30 Fog guard lamps31 Interior lamps32 Cigar lighter/clock33 Blower controls34 Compressor controls35 Cooling fans36 Power windows37 Sunroof38 Central locking (EXCEPT Japan)39 Central locking (Japan)40 Power seats41 Power mirrors42 Trailer auxiliary socket43 Theft alarm system44 Power distribution45 Fuse details46 Ground distribution47 Component location table48 Component location views49 Connector views50 Harness routing
Land Rover Discovery Electrical Troubleshooting Manual (1997 on)38 · Central locking (EXCEPT Japan)
38 · General

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)Central locking (except Japan) – 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

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