Auto door locks have a mind of their own? Replace your actuators!
 

I have been dealing with an annoying issue on my car for years now, but never was able to make much progress in diagnosing or fixing the issue. My car has had problems unlocking, where I would unlock the car with my alarm remote, the car would unlock, and then immediately re-lock three or all doors. I would often have to unlock the car five times for all doors to unlock and stay unlocked. Obviously, this was pretty annoying. I searched for solutions over the years, and all I seemed to find were recommendations to lube the hinge points for the lock rods inside the doors. The theory was that the hinges were getting sticky, preventing the door lock actuator from unlocking all the way, and if one of the front doors doesn't unlock all the way, the body control module (BCM) would then lock all the doors again. Well, I lubed my hinge points many times, and while it would sometimes seem to make the interior door lock move more smoothly, it never solved the problem.

I was talking with a buddy who is a real mechanic, and he said when door lock issues like that come up, it's almost always bad door lock actuators. The motors get worn out and have trouble pushing to fully unlock the rest of the system, so when the door only partially unlocks, the BCM freaks out and re-locks the door. Well, I had enough mucking around and decided to just buy new actuators for the front doors. They were about $75 each on RockAuto, and much to my surprise, they appear to be an OEM product in an aftermarket box! I bought the WVE brand, and they were made in Japan and even had a Nissan logo on them!

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As you can see, I snagged a bunch of actuators from cars at the junkyards in an attempt to narrow down the problem to one door or the other. If you look closer, two of the actuators are still attached to the rest of the lock mechanism, like they would be in the car. The actuator attaches to this with two screws to hold it in place, and the lever/arm (in the center) that moves the rest of the linkages just kind of slides in place. But when the junkyard parts didn't seem to help, I figured it was time for new parts. The problem with this repair is ease of access. My Haynes manual doesn't cover replacing the door lock actuators, and from my experience at the junkyard, I knew how hard they were to remove from the doors. The only reason I could remove them at the junkyard was because I took the whole lever/arms assembly out with the actuator. But I knew that reinstalling all of that was going to be damn near impossible since it's all tucked up way back in the door where you can't see or get to. My goal was to somehow remove the old actuator without the whole lever/rod assembly. The actuator is attached to the door with one bolt, and then to the lever/rod assembly with two smaller screws. You can access the screw towards the front of the car rather easily, but the rear screw is way back in the door where you can't see or reach. Certainly no tool can reach it either. So here's what I did to replace the door lock actuators without removing anything else from the car. It took a good deal of patience, which I'm not known for, small screw drivers, and a mirror.

First, I unbolted the window guide from the door by removing this bolt:

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Then I unbolted the actuator from the door with this bolt:

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Unscrewing the screw towards the front of the car was easy enough, but I still needed access to get to the rear screw. I achieved this by using zip ties to hold the window guide forward and out of the way of the rear screw:

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After some creative use of my mirror and flash light, I was finally able to get my screwdriver on the rear screw and get it out. Holy crap, it worked!!! I installed the new actuator, the bolt holding it to the door, and the front screw to the lever/arm assembly. I was unable to hold the second screw and reinstall it into the rear hole, but the actuator is secure enough without it.

There are the tools I used, nothing fancy:

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To be honest, I wasn't expecting much. Once I had my original actuators loose and free from the rest of the assembly, I tested them out by locking/unlocking the car to see if the lever went through its full range of motion. Most of the ones I pulled from the junkyard weren't moving all the way when I unlocked them, telling me they were worn out. Well, to my surprise and dismay, the ones that had been in my car appeared to go through their full range of motion, so I didn't have high hopes for the new ones fixing anything. Still, I installed the new ones and crossed my fingers. It's been over a week now, and so far (knock on wood) I haven't had s single problem. It's a miracle!!! I can't tell you how nice it is to come up to my car, press unlock, and it actually does what I told it to do!

Now, with that said, it's still a good idea to inspect all of your lock rods in your doors. I knew my front ones were well lubed and clean, but I rarely have the rear door panels off to inspect them. One day I happened to manually unlock my PS rear door, and I noticed it was harder than normal to manually unlock it on the door. Once I had the panel off, I spotted a potential problem:

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My rods were rusty! By itself this isn't much of a problem, however, when a rusty rod has to pass over another object, that rust causes friction, keeping it from moving freely. Well, as the rod goes back further into the door, it passes over a foam block with a paper/plastic covering. The rod is supposed to pass over the smooth paper/plastic over the foam, but my foam had gotten messed up, so my rods were rubbing against the foam, which had much more friction than the smooth cover it's supposed to be up against. I couldn't really salvage the foam piece, so I came up with a plan to minimize friction. I installed some split look tubing for wires around the problem rod where it passes over the foam block, so instead of rubbing up against the foam, it's rubbing against some nice smooth plastic!

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I lubed up the hinge points with some white lithium grease and the action of the lock was much smoother! I did all of this before installing the new actuators, so while it didn't solve my problem, I'm sure what I did will help it work smoothly for years to come.

I hope someone finds this helpful! Let me know if you have any questions.

Great post....in all the years and taking these car's ,fully apart. I have never seen those things.

Thanks! Yeah, they're really tucked up in there. It wasn't fun getting to them, but it was worth the effort!

After 24 years of 4th Gens and this creeping problem affecting enough of us, finally.... someone figured it out AND documented it for the rest of us to cheat/use!

THANK YOU!

Actually, I already have one of those! But I didn't think it would help with this project, as you need a real-time mirror in the door so you can try and get your screw driver on the rear screw. Trying to look at a screen just won't work for a project like this. Thinking about it now, what might have been even better is a small mirror with magnets on the back that you can stick to the door panel. That way both of your hands would be free, instead of trying to hold the mirror and the screw driver at the same time. But that also might not work, as your hand would likely block the view of the screw you're trying to access. I think I had to kind of angle my mirror from above so I could still see and access the screw.

Great thread. I guess I should pick up some actuators for the future.

Did you use one of these? Are they any good?

I bought one off Amazon, they're pretty much all the same thing just with different brand names stuck on them. Getting the software to work with the camera and a laptop can be annoying sometimes, but it does work and do what it's supposed to do. I've really only had to use it a few times in the few years I've owned it, but since they're so cheap, it's a nice thing to have around. Just don't expect to use it for this door lock actuator project.

95maxrider,

I found this thread via the search. Bumping to say thank you, this is exactly what I was looking for. ALL of my actuators are failing (half-locking doors) and the problem is exacerbated by the cold weather.

This is next on my list for the car. The current rockauto prices for our 4th gen actuators are astronomical, with the fronts costing $80+ each, and the rears costing upwards of $140 each. Sadly, these seem to be the best prices for these units.

Actuators for the 2000+ can be had for $10. wtf?

Visually, the parts look quite similar, but I don't see this working due to possible differences in the wiring harness and other random mismatches. Has anyone attempted to use a 2000 actuator in our vehicles? I was even considering grabbing one and, if it didn't fit right out of the box, I was tempted to see if I could crack it open and just swap over the motor into my current housing. Anyone ever gone this route? Interested in any feedback

You're welcome, I'm glad it was helpful.

I'm almost certain you would be the first one to try a 5th gen actuator in a 4th gen, and certainly the first to put the 5th gen guts in a 4th gen housing. I never tried to pop them open, so I'm not sure if they will snap back together properly or not. Given how cheap they are, I say give it a shot! These things are pretty simple devices, so if the connector plug looks to be the same shape, it very well could work. The thing that is most likely to give you trouble is the location of the screw holes.

Thanks for the reply!

In my parts searches, I actually found a set of four universal actuators on amazon for $13 shipped:laugh:.

The install looks to be fairly basic. They are due to arrive by this weekend, so I am going to dive in and rig them up. Will follow up with pictures.

I figure if they work - great. If they don't work properly, I'm only out $13:D

Thanks again, will follow-up with my progress later this week.

95MaxRider:

I missed this excellent and well-written how-to when you first posted it. Nice photos and documentation! Thanks for putting this together for us. :doublethu. It always amazes me how a simple mirror can be so helpful when working on cars and home improvement projects as well. My small collection has saved me many times!

Moderator - can you post this in the How-to's sticky please? Seems like we all might need this tutorial at some point down the line!

Bumping this thread since it's been a while :)

Interesting stuff!
We really need to know the result of the cheaper options here. I'm not paying hundreds of dollars.

My doors lock and unlock fine with the switch but there is often difficulty getting the key-fob to work. It's as if the signal is not strong enough but no amount of battery changing helps. I learned that the antenna is near the rear windshield, so that helps a bit. The auto locking happens only rarely, sometimes after the hood has been accidentally slammed shut.

My car might do this. I'll have to test this next time I get a chance.