Power door locks are a feature that has nearly become a standard feature on many newer vehicles. They make the task of locking the vehicle’s doors as simple as pressing a button on the key fob or inside of the vehicle. The door locks are electronically controlled, and as is the case with many other automotive electrical circuits, they will run their power through a relay.
The door lock relay is the relay responsible for sending power to the door lock actuators so that they can lock and unlock the vehicle. When the relay fails or has issues, it can cause problems with the operation of the door locks. Usually a bad or failing door lock relay will produce a few symptoms that can alert the driver of a potential problem that should be serviced.
Power door locks function intermittently
One of the first symptoms of a possible problem with the door lock relay are door locks that function intermittently. If the door lock relay has any internal or wiring issues, it can cause the door locks to function intermittently. The door locks may function correctly one moment, and in the next will cease to operate. This can be an inconvenience to the driver when trying to lock or unlock the vehicle.
Power door locks do not function
Power door locks that do not function are another common symptom for a problem with the door lock relay. If the power door lock relay fails, it will cut off power to the entire power door lock system and may cause them to not function correctly. For vehicles equipped with door lock cylinders, the door can still be opened using the key. However, vehicles without door lock cylinders will not be able to lock or unlock the doors until power is restored.
For vehicles with traditional style door lock cylinders and keys, a bad power door lock relay will merely disable the power door lock feature. For vehicles without door lock cylinders, however, this may make entering the vehicle difficult if not impossible if the doors cannot unlock due to a bad relay. If your power door lock system is having any issues, or you suspect that your relay may be having a problem, have the vehicle inspected by a professional technician, such as one from YourMechanic, to determine if your car needs a door lock relay replacement.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Door Lock Relay and was authored by Ed Ruelas.