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Problem with Rear Hatch Sensor


How can I fix the rear door lock sensor on our 2001 BMW 525I Sports Wagen so it closes completely. The electronic lock locks, but the light on the tailgate stays lit, and when you drive the car and go over a bump, it sounds like the door is ajar. Background info. The car is in excellent shape with 90k miles. We parked it over the winter, and when I attempted to start it up after 4 months the batter was dead so I had to recharge it before I could start it.

If you can hear the tailgate rattling, then it’s not closing properly, which is why the light stays on.

I’m sure there’s an adjustment for the latch. It’s the part on the body you want to adjust, not the part on the tailgate. The lock is not the problem, it’s the latch that holds the gate closed.

The dead battery has nothing to do with this.

I agree that the problem is the latch, but the latch on the BMW hatch back is not mechanical in the sense that the harder you slam it will insure it is closed properly. It closes very subtly, and when the sensor senses that the door is closed the latch electronically cinches the door fully latched… This is what it is not doing.

Well, nothing like replacing something simple and reliable with something complex that doesn’t work right. That’s progress for you.

Unless someone pops up who has analyzed and solved this problem, I think that you are going to have to work it out for yourself. Maybe remove the passive part of the latch and experiment with inserting it into the active latch to see exactly what is happening or not happening while still having the hatch open so you can see what is going on. Maybe the answer to how to fix things will be obvious.

If not, there is always the dealer. If all that is needed is a minor adjustment, maybe you’ll be able to escape without too much damage to your wallet.

There is always hope that someone will have experience with this… This is my wife’s car, and we live in a small town at the coast in Oregon. It’s an 1 3/4 hour trip to the closest BMW dealer in Portland.

Its pretty old. Has the whole thing ever just been cleaned and re-lubed? I’d spray the heck out of it with something like electronics cleaner and then re-lube it all with whatever is recommended. You can just stop by an auto parts store and tell them you need to clean and relube your hatch latch. (Just protect the paint).

This seems like a very narrow/specialized question. I suggest you google for a specialized BMW Forum. There are quite a few out there, and your chances of finding someone who had and solved this issue are much improved. Best of luck.

Actually, it is super clean. Early last year we had a similar problem, which we did take to the dealer to fix. All of the doors would not lock or unlock with he key. This tailgate stayed ajar as it is now. At that time, the dealership fixed it, and said it was the sensor on the gas door…

I don’t know what you mean by “super clean” or what the dealership actually did for the past problem. But I’m not talking about something that you can see or something that would ever get cleaned - even by a carwash or detailer. I’m talking about old, dirty, stiff grease up inside the internals of the whole mechanism. This can interfere both with the proper mechanical and electrical functions. The cleaning would involve a residue free grease cutting solvent with a little spray tube attached to blow out all of the guts of the thing.

By super clean I mean, that I would feel safe eating off of the latch. There is NO old dirty stiff grease on the inside of this latch…!!! I am very confident that the problem is with the sensors and not a mechanical problem with a stiff dirty part.

Hey, whatever you say man. Sorry you seem to be annoyed by free advice that might result in spending almost no money to potentially solve a problem. No matter how outlandish you find the idea to be I assure you that the suggestion is not off base. For one thing, if you did use an electronics cleaner, it would clean the electronics - I fully understand that the problem may be solely electrical. Sorry to have tried to help.

I am sorry I am not annoyed with you, just frustrated with the complexity of the BMW. I called the dealer, and the shop foreman thought it might be a worn wire in the wire harness that goes up through the hinge in the door. But, the only way they could be sure was to bring it in… Alas it would be nice to have a nice simpe mechanical only car…

It occurs to me that if the hatchback light is staying on, it may be controlled by a switch separate from the latch. You may be able to get the light to stay off by putting a pad (six or eight layers of duct tape for example) on the opposing part of the hatch. You might even be able to get the hatch to quit rattling with a similar pad or three. But you’re likely to have some leakage when it rains – which in coastal Oregon is most of the time?

Anyway, I think a BMW forum would be a good place to visit. And you might call the service department at the dealer in Portland. Maybe they’ll know exactly what is wrong and whether you or a local mechanic can fix it.