Door lock unlock themselves, when Cruiser is shut off (1 Viewer)

[frozone]

Door locks unlock themselves, even when Cruiser is shut off

I've got a poltergeist in my Cruiser. I searched the threads but didn't find one on this so if it's already been covered, my apologies.

A few months back, I started noticing my locks making a clicking sound, basically the sound you'd get if you pressed unlock and the car is already unlocked. This would happen when I was driving and literally could go on the entire trip ranging from every few seconds to fairly well spaced apart. The locks were trying to unlock themselves.

If I locked the car while driving, it would unlock. Eventually this problem got worse and now my car will unlock itself even after I've parked it and walked away. I'll come out to my car, knowing I've locked it, and it's unlocked. It's done it many times while I'm standing there. I lock the car (with the button), close the door and it unlocks. I can do this over and over. Same thing if I close the door and lock with the key or with the remote.

One other point, that I'm not sure is relevant, but a few weeks before all this started, my remote went haywire. It would unlock, but not lock the car (or vice versa, can't really remember now). I changed the battery and it still had issues. I monkeyed around with it, can't remember what I did, but eventually it started to work again, but then eventually would go back to only being able to do one thing and only at very close range. Seems like it could be related.

I'm not using my remote right now since the housing broke, so I'm just using a chipped master key to manually unlock and lock the door. It doesn't matter whether I use the key, the remote or the lock button, the symptoms are the same.

I've tried different things. Lubed the actuators, checked the dome light push button, pulled out the lock module and unhooked wires. A few weeks ago I pulled the wire harness that seems to control the auto window down function. My lock problem went away, I thought I'd figured something out. But now it's back just like before.

Basically, something seems to be telling the locking mechanism that it needs to unlock, almost like the function that keeps you from locking the door if the key's in the ignition, the car's running and you try to lock the door while it's open.

I'm at a loss. It's resolved itself twice now, once for about a week, the other for about 3 weeks. But it keeps coming back.

 

[Trunk Monkey]

I'd check the contacts in the lock/unlock buttons by the window controls.

 

[ToyotaDon]

I would check the installation of the door key cylinder switch on the door where you had the harness disconnected. If it seems to be installed properly, disconnect it and see if the problem goes away. If the problem goes away, replace that switch.

 

[frozone]

I had the window and lock controls completely disconnected and it still does it, so I've ruled out the control module itself.

I can lock the door from the passenger side key cylinder and I still have the same problem, but I haven't thought to look at the key cylinder so I'll check it out.

Is there a sensor in the actuator that tells the security system that door is open or closed?

 

[Yotato]

Sounds like your power door lock relay is stuck open or shorting out.

 

[frozone]

Any way to test for this without having to buy a new relay? How do I zero in on the relay and determine if that's the root cause? Without buying the new relay first?

 

[2000UZJ]

I wish I had your problem. Mine locks itself randomly (even when running and I hit unlock before getting out). I know have to roll down a window if I want to get out and talk without turning off the 100

It's annoying. But if I forget to lock it I know it will just lock it self. Which can('t) be helpful

 

[re_guderian]

Does this happen to all doors, or just one? When you say "door lock controls" are you talking about just the ones in the driver's side door? Also, there is a "door lock ecu" that may be malfunctioning. Do you have a FSM? It has the procedure to troubleshoot the system. What year is your cruiser? I can scan to pdf the section tonight if you need, but mine's a 2000. Not sure how universal that system is year-to-year, though I would think very similar. Also, others here have had problems with water leaks around the windshield playing havoc with ECU's. Do you have any symptoms of that?

 

[Yotato]

You can test a relay by following this: How to Test a Car Relay | eHow.com

You can also temporarily switch the relay for one next to it. Keep in mind that by swapping relays, you swap problems.

If that isn't the problem, test wiring and contact points for good continuity and then lastly, the door lock ecu.

 

[frozone]

Does this happen to all doors, or just one? When you say "door lock controls" are you talking about just the ones in the driver's side door? Also, there is a "door lock ecu" that may be malfunctioning. Do you have a FSM? It has the procedure to troubleshoot the system. What year is your cruiser? I can scan to pdf the section tonight if you need, but mine's a 2000. Not sure how universal that system is year-to-year, though I would think very similar. Also, others here have had problems with water leaks around the windshield playing havoc with ECU's. Do you have any symptoms of that?

Thanks for your help. I don't have a service manual, so a scan of the trouble shooting section would be appreciated. The symptoms are the same with either the driver or passenger lock mechanism and key lock mechanism. In other words, I can flip the switch on either side or lock with the key cylinder on either side and the entire system (all doors) will still unlock itself. My sense is that this has nothing to do with the electronic lock modules or the key cylinders themselves.

I've been leaning towards something having to do with the driver side door actuator or something with a relay, but that's purely hunch, no science or proof. This is the first problem I've had since I bought the vehicle over 3 years ago, I'm not familiar with the ECU issues but will research here on the forum.

 

[teambell]

What year is your rig????

He needs to know the year to see if it is the same as his FSM....

 

[frozone]

He needs to know the year to see if it is the same as his FSM....

It's a 1999 Land Cruiser.

 

[Topoguide]

Did you get it figured out? My truck has stated having problems that seem to fit your description of the remote going haywire.

 

[MetroWest]

Also check the tailgate lock cylinder switch and wiring harness for a potential intermittent short. A dirty / damp cylinder switch was actuating my locks (and alarm at one point)

 

[iseibert]

I had this exact same problem about a year ago. Mine would lock and unlock while driving and in a parking lot, but very intermittently and I could not determine a pattern that would cause the problem. Then I read a post about the tailgate locking mechanism having dirty contacts for someone on this forum. It took about 10 minutes to remove the carpeting and get to the contact, which looked clean. I took it apart and made sure that blew any dust out, put it back together and haven't had the problem since.

This forum is a wonderful resource of information!

 

[Topoguide]

Thanks... mine is definitely random. I will have to check that out.

 

[2000UZJ]

Thanks... mine is definitely random. I will have to check that out.

I had strange key issues last week, it was fixed by putting it in the ignition on ACC and letting it sit for about 30 minutes while listening to some music... strange, but true.

 

[Chicagomexitalian]

It's a 1999 Land Cruiser.

Its the body control module(bcm) same was happening on my escalade.

 

[NorthShoreLC]

I know this is an 8 year old thread, but it sent me in the right direction and I solved my issue. 2005 Hundy.

Had the phantom locking unlocking thing. The wiring harness to the tailgate right near the hinge was shorting. I could move the harness with my fingers and the doors would lock/ unlock). One completely broken wire, 3 nearly though and toasty. Opened it up, soldered, heat shrink wrapped, closed back up. Problem solved.

 

[BigZPatt]

I know this is an 8 year old thread, but it sent me in the right direction and I solved my issue. 2005 Hundy.

Had the phantom locking unlocking thing. The wiring harness to the tailgate right near the hinge was shorting. I could move the harness with my fingers and the doors would lock/ unlock). One completely broken wire, 3 nearly though and toasty. Opened it up, soldered, heat shrink wrapped, closed back up. Problem solved.

Where do I find this wiring harness and how do I access it? I've got the same issue and the dealership diagnosed the problem as the BCM (Body Control Module). Not only do my doors lock/unlock themselves but power is remaining on and draining my battery - I'm wondering if they're related.