Car door switches are one of the most basic, yet often overlooked items on any car alarm system. They detected if the door is open or shut so are the first layer of protection for any security system.
Even if you don’t have an alarm its important that all of your door switches work, as without them you risk locking your keys inside your car!
Most vehicles have a timer that starts when you press the unlock button on your remote control. This timer is cancelled if the cars body control module has detected a door being opened. If a door is not opened (or seen to be opened due to a faulty switch) the doors will re-lock. Typically after 30 seconds. Note; the timing can vary between manufacturers.
Testing your car door switches
Most cars have a display in the instrument cluster indicating if a door is open, some will simply have one symbol for all doors,
You may need to turn your ignition on for this display to work. Open each door one at a time (leaving the other doors closed) and see if the dispay shows that the door is open
If your car does not have a display then turn the ignition on and see if the courtesy light turns on and off with when each door opens and closes (you may need to wait a couple of seconds for it to fade out on some vehicles). Of course, you’ll need a working courtesy lamp to do this test. If you don’t have a working one the check the fuses and the bulb as its nice to have a working one when it gets dark!
Service or replacing your car door switches
If after testing your door switches you discover that one is not working then you’ll probably need to repair or replace it. I say probably because there is the possibility that it is a broken wire or connection.
If you have a switch like the one shown in the photo at the pop of the page then get a screw driver and remove it. Look for signs of corrosion and clean the contacts if
Some switches are sealed so cleaning up the contacts is not possible. If this is the case then the switch will need replacing. You can normally order one from your local dealership.
Can’t find a switch?
If there is no visible switch below the door latch or below the door hinge then you may have a switch that is built into the door latch. These are common on boot switches or doors found on some late model vehicles. Again these can also fail, but replacing them is not a simple job.
Of course this is something I test for whenever I install an alarm and I’ll advise you if you need a replacement. If you know you have a faulty switch before I work on your vehicle then please let me know. I’m normally happy to replace it for you if you bring a new one along for me 😉