[e4tmonkieshyt]

Hi,

I've been dealing with my driver side door unlocking but not locking. I have already checked and replaced fuses as well as replace the door lock actuator, and I still have the problem. I have checked the forums and tried everything I could, can anyone help me figure out what is wrong?

[Chriztofor]

Charge your battery. It may be low or failing.

[e4tmonkieshyt]

Thanks for the tip, I'll try letting the battery charge overnight and see what happens tomorrow.

[GoRomeo]

Try your other Keyfob.

[e4tmonkieshyt]

Originally Posted by GoRomeo

Try your other Keyfob.

I tried my other key fob already, checked and made sure all fuses are good, replaced the door lock actuator, and checked the wiring to see if anything is wrong. Nothing worked, but hopefully I'll be able to figure this out after I fully charge my battery and give it another go.

[GoRomeo]

I see. I will check the wiring next then. Hopefully its just a low battery. In my case I did run my car with a low battery for almost 2 yrs and never had any issues with locks. Only features such as REST, Defrost and auto dimming on mirrors. These last 3 did not work due to a low battery. Keep us posted and good luck.

[Surly73]

There seems to be a whole lot of stabbing in the dark. Based on experience from other BMW models, it may be a failing microswitch in the door lock actuator.

It's not going to be fuses - unlocking works so there's power, the problem is only in one door.

It's unlikely to be wiring - these devices are usually nodes on a communications bus - if they unlock they have power and communication connectivity so they're fine. Depending on the exact construction it's still possible.

I think it's unlikely to be a low battery - it unlocks, only the driver's door doesn't lock, and the locks are the only thing acting weird? Sounds fishy.

It could be a bad fob battery, but I believe the car is also supposed to tell you if the fob battery is low or failing. I haven't seen this in the E90 manual, but BMWs did this 12 years ago. My non-rechargeable E39 fob (built in 1998 before the car told you fob battery status) would indicate low battery by always unlocking but requiring a couple of presses to lock. Try the other fob and you'll rule this in or out.

If it were mine, I would disassemble the door, remove the actuator and clean it with contact spray. Again my firsthand experience is from other models, but there is a microswitch in the actuator which determines the rotational position and allows the single lock/double lock to function properly. I have seen an actuator (again, E39) which started to misbehave because this microswitch was dirty. One puff of contact cleaner and a couple dozen toggles by hand and it was good to go for years longer until the car was sold.

[e4tmonkieshyt]

Yeah, I replaced the actuator with a brand new one from BMW and still had the problem. After letting the battery full charge and double checking the fuses, wiring, and connections. I finally worked again. Had to reprogram the windows, but It finally works.

Thanks for all the tips.

[Chriztofor]

No problem! Next time just follow my suggestion first.