Cars have been equipped with door switches for quite some time now. The car’s computer monitors the switch and alerts the driver when it thinks one of the doors isn’t closed all the way through. This is a safety measure to prevent any doors from opening while you are driving.
Although this is a relatively simple system, there are a few odd faults that can occur with the switch causing the door open warning light to come on and stay on.
What the door open warning light means
As mentioned before, when the light comes on, the computer thinks one of your doors isn’t closed all the way. Every time you start the engine, take a quick glance at the dash before you start moving to make sure this light isn’t on. If it is on, close any doors that may not have shut all the way and the light should turn off automatically. Keep in mind that the trunk and hood may be included as a door so check them if closing the cabin doors doesn’t turn off the light.
Some cars also indicate which specific door it thinks is open to help you figure out which one you need to close. If you start driving and then notice the light is illuminated, you should pull over safely before trying to close the doors. Opening any doors while on the road can be risky and dangerous.
Typically, the issue may be with the door switch as due to repeated use, the mechanical parts of the switch break. A replacement switch should solve this problem. Dirt from the air can also get trapped inside the switch preventing it from opening and closing. Spray some lubricating oil, such as WD-40, on the switch to try and clean the dirt out. Opening and closing the door a few times should also help dislodge any dirt. If cleaning or replacing the switch doesn’t shut the light off, have the associated wires and connectors inspected for any damage.
Is it safe to drive with the door open warning light on?
Most cars have 2 “stages” to their locks. Even if the door is slightly ajar, it will still be locked down to prevent it from swinging open. As mentioned, pull over somewhere safe to check all the doors.
While the light doesn’t affect driveability or performance of the vehicle, it can cause some other issues. For example, some cars won’t let you lock the doors if one of them is open. Many of us keep valuables in our cars and not being able to lock them in is very risky. If you are unable to lock the doors, you should only use the vehicle if absolutely necessary, but be sure to remove any valuables beforehand.
If you are experiencing any issues with your door open warning light, enlist a certified technician from YourMechanic to help you diagnose any problems.
This article originally appeared on YourMechanic.com as What Does the Door Open Warning Light Mean? and was authored by Spencer Cates.