Central lock intermittently working

Question

My central lock was working fine until yesterday. When I used the key, it clicks but doesn't unlock the doors as it should. Then I tried the second time, no clicking sound this time and nothing happens as well.

What I did is use the passengers side door to gain entry. I can use the key to unlock it but if I do not hold it, it returns to lock position. So you need to hold it on unlock position and open the door simultaneously.

Upon entry, I tried manually unlocking the doors using the central lock but it wouldn't badge. So I started the car and after a few seconds, tried unlocking the doors again and to my surprise it unlocks. I tried a few times and it was intermittently working.

Before this happens, my car was exposed to continuous heavy rain for about two days (just parked in front of the house). So my questions are:

1. What is likely the cause of this?
2. Does a wet key hole (soaked probably) or wet key affects the central lock system?

Right now it is working, but I don't want to be caught off-guard where it doesn't unlock or worse won't lock during trips.

Answer 1

The problem persist and I remove the door card yesterday. I figured that the reason is the mis-aligned rod connected to manual lever used to open the door from the inside. It somehow gotten loose from the guide and blocks the spring/switch (it looks like a spring) connected to the actuator. So there is no way for the actuator to work on-off.

I also figured that water ingression doesn't have something to do with it as the actuator and electrical parts are far from the water entry and water ways inside. The key works mechanically with a rod connected to the actuator and there is no way the water could actually get to the switch.

I also inspected the wires and some just needed re-harnessing and all is good with no abrasion or exposed wire. Actuator working ok as well. I don't think it can easily broke as it looks really solid.

Thanks to all who responded. I posted this as answer in case someone experienced the same. Btw, model is Mazda 323F 2k model. My doors are not keyless entry and not power window so removing the door card is quite easy.

Answer 2

As Zaid says, it sounds like a problem with the actuator. Are you trying to open it with the key, or a remote? I presume key from the way you've phrased it?

If it's the key, then it'll be the actuator in the driver's door - i.e. the switch that is activated when you turn the key. I suspect from your description that water has got in somehow, and caused a short to make it think the key is in the 'lock' position - hence it trying to lock the door again when you used the key on the passenger side.

You might be able to tell by taking the door card (the inner trim of the door) off and looking for signs of water ingress, otherwise I suspect it'll be a case of removing the actuator and testing it...

Answer 3

There are two things that could have gone wrong.

• The Actuators present in the driver side door which control the lock/unlock possibly due to rain. I am specifically saying driver side door since only it has 4 wire connections, two for the actuator and 2 for connecting to the central locking chip. So in essence it can control all other doors.

• The main board which is usually present near the steering column which actually sends signal to each of the doors to do what they do.

Unfortunately there is no real way of testing if its actually gone wrong without manually inspecting it, what you can do is, test if its working fine for sometime and if its fine for days they its as zaid says , due to water and might have caused malfunction.