Key will lock doors and trunk, but not unlock doors on 2004 BMW 645Ci

ANSWER : Your central locking system may have been designed with a control module in the circuit. This is a small computer that is responsible for controlling the different functions of a particular system. It is possible that the module for your central locking system may have shorted out internally preventing particular functions from working properly. I would recommend having a certified technician test your central locking module to determine if all of its functions are working properly.

ANSWER : Hi there. The first thing I would do is try another key to see if you get the same results from the key control. If the separate key works, then it is the key that is the problem.

If not, then I usually start by reprogramming the receiver module first. If that does not help, then the module may need to be replaced.

As for the window, if a window will go down and not up then the left actuator is bad. It takes more effort to close a window, so a failing actuator cannot close the window. If you need to have this repaired, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose your door locks and windows so that you can have the correct repairs done.

ANSWER : This is often related to a malfunctioning door lock actuator, a blown fuse or a faulty power door lock switch. When you use the door lock switch in the car it sends a signal to a relay which then activates an actuator inside the door. The actuator is the final step in the process in that it is a small motor with a set of gears that actually locks and unlocks the latch mechanism inside the door allowing the door to open. When this motor is bad, the latch mechanism will fail to operate and cause the door not to unlock as it is designed to. In the case of a bad door lock relay, the power, normally needed to send the signal from the switch when you activate it to the actuator motor is not there. This means the relay is not allowing the circuit to be completed and the actuator motor is not activated. Any of the above may cause your power door lock switches not to work properly and should be diagnosed by a qualified mechanic. I would suggest having a professional from YourMechanic come to your location to take a look at the door locks in your vehicle.

ANSWER : Hi there. The door lock cylinder has either an object in side it causing the key to not fit or the pins inside the cylinder has fallen into the key hole. I recommend replacing the door lock cylinder. If you need further assistance with your key not working in the door lock cylinder, then seek out a professional, such as one from Your Mechanic, to help you.

ANSWER : Hello. Further testing should be done to help solve your problem. Being that the door unlock reprogramming procedure has already been done and the fuses have been checked there’s not much left it could be. When you hit the unlock button you should hear a little noise in each of the doors. If you hear the noise that means that the motor inside of the door actuator is working therefore it is likely the actuator itself as the problem. Though if you do not hear any noise that means it is likely the motor inside of the actuator. The actuator motors are very common failure on Lexus. The Lexus Community is almost an uproar because the a L in Lexus should also stand for luxury but there have been widespread simple problems reported such as this. A technician such as those we have here at yourmechanic will be able to diagnose your door lock issue for you firsthand. But if you consider following the test I suggested that should help you narrow down to a solution as well.

It may also be a beneficial to take a door panel off and probe a multi meter to the door actuator connectors to ensure they are receiving the proper power and ground when the buttons are pressed. If they are that only leaves two things that can be at fault. The door actuator or the motor inside of the door actuator.

ANSWER : If the same problem is happening even when you use the inside door lock switch then the most likely cause of the locks not moving is going to be weak actuators. You should replace the drivers lock actuator first since it is used the most and you will see it fixes the problem. Then you can replace the other doors as needed.

ANSWER : Hi there. These door issues are common on this vehicle. Most of the time the main issue is the master door lock switch on the driver door. It sounds like you already replaced that. As for the sliding door problem, most of the time, this is a failure within the door module or it can be a connection issue.

I typically take the door apart and check the connections on the module and inside of the door just to make sure that there is nothing apparent in there. If the connections and the wiring are fine, then I use a scan tool to check the module to see what the inputs and outputs are doing. If you need to have this looked at, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose your door problem and recommend a repair.

ANSWER : Hello, thank you for writing in. The vehicle may be having an issue with its body control module. Due to the locks doing this on their own, and the issue with the key-less entry (which works on its own circuitry), the issue is likely the components they have in common. This will include the body control module, fuse systems, or a short somewhere. Testing will need to be done when the system is experiencing the symptoms, and you may need to replicate them at the needed time. Due to the timing in which this happens, you will want to locate where the extra supply of power to the locks are coming from. Find this, and you likely will find your issue. For more help resolving the issue, contact our service department to schedule an appointment.