Fixing Rear Door Lock Issues in a 2018 Nissan Murano
Table of Contents
- Introduction
- Diagnosis of rear door locks
- Checking the wiring diagram
- The role of the Body Control Module (BCM)
- Potential problems with the lock and unlock switches
- Removing the piece to access the BCM
- Testing the rear door lock with a multimeter
- Troubleshooting the reverse polarity door lock switch
- Installing the new BCM
- Reprogramming the BCM and keys
Introduction
Today, we will discuss the issue of rear door locks not working in a 2018 Nissan Murano. The customer has complained that both the left and right rear door locks do not unlock or lock using the power locks. In this article, we will go through the diagnosis process for this issue and provide a step-by-step guide on how to fix it.
Diagnosis of rear door locks
When multiple door actuators fail to work, the first step is to check for common components among them. In the case of the 2018 Murano, the left and right rear door lock actuators have the Body Control Module (BCM) as a common component. Therefore, we need to start by checking the output signal from the BCM to the actuators. However, before touching the car, it's essential to rule out any problems with the lock and unlock switches.
Checking the wiring diagram
By analyzing the wiring diagram, we can determine that the power lock switches have only one input to the BCM. This input is likely a communication line, such as a Lin bus (Local Interconnect Network). It is improbable that the problem lies with this input because the front door locks are working correctly. Thus, we can move forward and focus on the BCM's output to the rear door lock actuators.
The role of the Body Control Module (BCM)
To access the BCM, we need to remove a piece in the car. The BCM is responsible for controlling various functions, including the power door locks. After removing the necessary part, we can proceed with testing the rear door lock using a multimeter. By connecting the multimeter to the yellow and brown wires, we can measure the voltage and determine if there is a problem with the reverse polarity door lock switch.
Troubleshooting the reverse polarity door lock switch
According to the testing results, it appears that the reverse polarity door lock switch is not functioning correctly. When activated, the voltage should change from approximately 0 volts to 12 volts or vice versa, indicating the lock or unlock state. However, in this case, there is no change in voltage, indicating a malfunction in the switch. This issue needs to be addressed by either repairing or replacing the switch.
Installing the new BCM
Once the faulty reverse polarity door lock switch is dealt with, the next step is to install a new BCM. This process requires removing the old BCM and replacing it with the new one. It is important to ensure that the new BCM is programmed and configured correctly for the vehicle.
Reprogramming the BCM and keys
After the new BCM is installed, it needs to be reprogrammed to work with the vehicle's keys. This process involves using a diagnostic tool, such as the Consult III Plus, to configure the BCM and program the keys. It is crucial to follow the manufacturer's instructions and perform the necessary steps to ensure proper reprogramming. Once completed, the door locks should be fully functional again.
Overall, diagnosing and fixing issues with rear door locks can be a complex process, but by following these steps and utilizing the appropriate tools and techniques, it is possible to resolve the problem effectively.
⭐️ Highlight: Diagnosing and fixing rear door lock issues in a 2018 Nissan Murano can be a complex process, but by following the proper steps and using the right tools, it is possible to resolve the problem effectively.
FAQ:
Q: What is the most common cause of rear door lock failure?
A: In most cases, the failure of rear door locks can be attributed to a faulty reverse polarity door lock switch. This switch controls the lock and unlock functions of the door locks and can malfunction over time.
Q: Can I fix the rear door lock issue myself, or do I need professional help?
A: While some DIY enthusiasts may be able to diagnose and fix minor rear door lock issues, it is generally recommended to seek professional help for more complex problems. Professional technicians have the experience, knowledge, and proper tools to carry out the necessary repairs accurately.
