Information on Fords Proximity System
Key fobs sends coded high frequency radio signal in the mechanical key when buttons are pressed going to the RF receiver located above the headliner in the vicinity of the overhead console. The signal will pass over a serial data line to the GEM (Generic Electronic Module), where it will be decoded. If the signal is valid or recognizable, the GEM will send an appropriate command over the CAN (Controller Area Network) data bus to the modules to perform such feature like lock, unlock, trunk, panic and remote start.
Below are some of the things that affects the responsiveness of a module:
? Frequencies from other devices such as cellphones can always interrupt the signal that are being sent to the radio transmitter or receiver.
?The key is damaged, some wires are loose, or the module itself is failing.
?The battery in the key is weak or dead which needs to be replaced immediately.
? The overload protection of the door latches is active (after too many operations).
As well as remote keyless entry, the vehicle can be locked and unlocked using the lock cylinder in the driver’s door. The lock cylinder is mechanically connected to switch, which is linked to the GEM.
What is a Central Locking Unit?
The central locking system does the locking and unlocking of all the doors and the tailgate/luggage compartment lid so that they cannot be accessed from the outside of the vehicle using the interior door handles.
The central locking function activates if:
?A key is inserted into the ignition and was turned to the LOCK position.
?The LOCK button on the remote is pressed.
?The interior door handle is pushed inwards.
When the central locking function is carried out, all the doors will cycle (locked and unlocked) if one of the doors was not completely closed. The system will automatically return to its last state of central locking (or double locking) on if:
?The vehicle was unlocked using the key fob.
?None of the doors or the tailgate/luggage compartment within 45 seconds.
?The ignition is not switched ON.
Central locking is confirmed by two flashes of the turn signal lamps, when the locking process is completed.
Double Locking System
Double locking systems works the same as the central locking unit, it prevents the doors from getting opened using the interior door handles outside of the vehicle. The double locking function id activates when:
?The key is inserted into the ignition and was turned to the LOCK position twice within 3 seconds.
?The LOCK button on the remote was pressed twice within 3 seconds.
As an indicator, vehicles with double locking systems will flash the parking lights twice, once the double locking process is completed. The ordinary central locking in this case will not be signaled via the turn signal lamps.
Luggage compartment lid latch.
GEM or the Generic Electronic Module is the one responsible for sending commands to open the trunk or tailgate/luggage compartment lid latch. The input command come from the external lock switch, receiver or remote going to GEM. Trunks do have a certain feature that automatically locks when it is closed.
The door latches have an electric motors and each motors are activated by the front or rear door module. When the door latch is locked, the exterior door handle is disengaged from the door latch.
Door latch has a control switch and this switch monitors its position then reports the information to the front and rear door module. This information is sent to the GEM for use in warning systems, locking functions and anti-theft alarm systems.