Doors lock automatically after cranking engine? Help

[Zinno30]

Hi guys,

I have tried the search tab but have been unsuccessful in finding an answer to my locking issue. I have had the car for less than 4 months and have realised this issue when I installed a new battery. Here is the things I have tested;
My central locking works when I lock and unlock with key. All doors lock individually from boot and passenger door, but my driver side door lock is faulty and does not allow me to lock from that hole or unlock. I know central locking works because when I try from passenger or boot, it locks and unlocks all doors. I have ordered the famous rebuild door lock cylinder kit from ebay to fix my driver side door lock. There is an alarm light on radio which needs to be unlocked by getting radio code and I can not physically see any alarm systems on my vehicle. I have not checked the under panel yet to see if any systems hiding..

My issue is that the car randomly lock all doors when I place the key in the ignition and start the engine. So every time I start the vehicle, I have to pull the door pin to unlock doors if I am in or worse if I start vehicle in garage to warm it up and accidentally close door to get back to it later, 15 seconds in to warm up, the doors lock and I have to grab my spare key from inside the house to unlock vehicle to get in while it is running. LOL driving me crazy. Could it be my faulty driver side door lock cylinder causing all this? Any ideas please?

[AndrewBird]

If the key fits in the door and will turn, the lock cylinder is fine. No need to rebuild it.

It definitely sounds like an aftermarket keyless entry system. I'd pull the knee bolster and take a look.

[Zinno30]

The key fits. But does not turn either way hence why I can't lock or unlock vehicle from driver door. Something definitely wrong with it hence why I ordered the kit. I shall check the underpanel in that case and hopefully you are right..

Thank you :)

[reelizmpro]

That's typically a programmable feature of an alarm or keyless entry system.

[Zinno30]

Thank you guys, I really appreciate the feedback. I will check it out on the weekend. I have realised that there is a tiny non-flashing alarm light on the bottom end of steering column and who knows what the cover is hiding. Keep you posted..