Did some research and found out that the problem with central locking is mainly due to the following:-
1. Actuator for the door lock/unlock.
2. Dead Bolt Actuator
3. Loose connection
4. GM5 or GMV or ZKE5 (depending on which country you are from)
Symthom of GM5 module problem :-
1. Mostly can lock but intermittently cannot unlock.
2. Need to use key to manually open the door on driver side.
3. Passenger door and rear door cannot be open by the inside door handle.
4. Internal "LOCK" push button on gearshift console also cannot open all doors.
5. Sound of "click" of the door trying to open but cannot open when the internal "LOCK" push button is activate.
If you have ALL of the aboves, then your problem is 99% GM5 module.
The BMW locking system basically consist of 2 actuators.
One actuator is for the lock/unlock function and the other actuator is for the deadbolt locking.
The deadbolt is activated inconjuction with alarm system and will prevent the door from opening even you use the internal door lever.
This is the security measure of the alarm system and it will prevent somebody from entering your vehicle even if they break your window pane.
The 2 actuators is similarly applied for all 4 doors and 2 door for coupe model.
The GM5 have 4 relays to switch all the 8 numbers of actuators plus another actuator for the petrol filling cover.
However, due to the configuration of the 4 relays, one relay is always configured to switch all the 9 devices at the same time causing the contact to wear off prematurely. (In my opinion, this is an inherent flaw in the design).
When the contact is worn out, resistance will increase between the contact surfaces and hence will reduce the current flow to properly switch the deadbolt actuators and lock/unlock actuator.
If the deadbolt actuator fail to be released, it is impossible to open the door.
You can confirm the deabolt is NOT release when you cannot open the passenger door by the internal door handle.
However, the driver deadbolt actuator can be released manually by using the key. Countermeasure.
1. Change the GM5 module (Best solution and most expensive)
2. Replace the affected relay (DIY but difficult to buy the relay as it is specially made)
3. Clean the relay contact (DIY but will only as long the contact surface is clean)
4. Disable the deadbolt actuator by removing the wire to this actuator at the GM5 module.
This will still enable the door to be lock and unlock but will not prevent somebody from entering the vehicle. 5. Insert a emergency switch to bypass or switch on the deadbolt actuator to release the deadbolt. The above is based on theory. I will try to DIY when I have the time. Note, incase you happen to lock yourself in the car and cannot open the door from inside. Dont panic. Just wind down the window pane and open the door with your key.
1. Actuator for the door lock/unlock.
2. Dead Bolt Actuator
3. Loose connection
4. GM5 or GMV or ZKE5 (depending on which country you are from)
Symthom of GM5 module problem :-
1. Mostly can lock but intermittently cannot unlock.
2. Need to use key to manually open the door on driver side.
3. Passenger door and rear door cannot be open by the inside door handle.
4. Internal "LOCK" push button on gearshift console also cannot open all doors.
5. Sound of "click" of the door trying to open but cannot open when the internal "LOCK" push button is activate.
If you have ALL of the aboves, then your problem is 99% GM5 module.
The BMW locking system basically consist of 2 actuators.
One actuator is for the lock/unlock function and the other actuator is for the deadbolt locking.
The deadbolt is activated inconjuction with alarm system and will prevent the door from opening even you use the internal door lever.
This is the security measure of the alarm system and it will prevent somebody from entering your vehicle even if they break your window pane.
The 2 actuators is similarly applied for all 4 doors and 2 door for coupe model.
The GM5 have 4 relays to switch all the 8 numbers of actuators plus another actuator for the petrol filling cover.
However, due to the configuration of the 4 relays, one relay is always configured to switch all the 9 devices at the same time causing the contact to wear off prematurely. (In my opinion, this is an inherent flaw in the design).
When the contact is worn out, resistance will increase between the contact surfaces and hence will reduce the current flow to properly switch the deadbolt actuators and lock/unlock actuator.
If the deadbolt actuator fail to be released, it is impossible to open the door.
You can confirm the deabolt is NOT release when you cannot open the passenger door by the internal door handle.
However, the driver deadbolt actuator can be released manually by using the key. Countermeasure.
1. Change the GM5 module (Best solution and most expensive)
2. Replace the affected relay (DIY but difficult to buy the relay as it is specially made)
3. Clean the relay contact (DIY but will only as long the contact surface is clean)
4. Disable the deadbolt actuator by removing the wire to this actuator at the GM5 module.
This will still enable the door to be lock and unlock but will not prevent somebody from entering the vehicle. 5. Insert a emergency switch to bypass or switch on the deadbolt actuator to release the deadbolt. The above is based on theory. I will try to DIY when I have the time. Note, incase you happen to lock yourself in the car and cannot open the door from inside. Dont panic. Just wind down the window pane and open the door with your key.
