Power locks unlocking on their own

[Grebus1]

The power locks on my '97 (w/o keyless entry) are unlocking on their own. It started this morning and has been intermittent since then. I hit the lock button on the switch and they will lock, but after awhile they will unlock without me touching anything. This afternoon I parked the car and locked it, when I came back a few hours later all the doors were unlocked (not real comforting). Happens with or without the key on and/or engine running. It was cold overnight, but not that bad (about 25-30 deg.). I lubed the lock cylinders, door latches and door handles about an hour ago and am waiting to see if that makes a difference. Any thoughts or suggestions? Also, is there a way I can just disable the power locks and go without them by pulling a fuse (in case this is something more involved like a module)? Thanks in advance...

[shorod]

It appears that if you were to remove the fuse for the power door locks, it would disable the accessory delay relay (which allows you to roll windows up, close the sunroof, etc. for 45 seconds or so after turning the ignition off if a door is not opened first) and the left power seat (if equipped).

Lubing the door latch assemblies may have an effect since the door pin switches are integrated into the door latch assembly in your Taurus. However, this would typically not cause an unlock condition.

I wonder if by chance the "key warning" feature is acting up. There is a switch in the ignition key cylinder switch that is used for various features such as the "lights on" chime, etc.

My recall is that another function of this switch is to alert the Generic Electronic Module (GEM) that if the key is in the ignition key switch, a door is opened, then the doors are locked, the GEM will unlock the doors when closed to prevent you from locking your keys in the car. This may only work is the car is running, I don't recall for sure. Maybe the GEM thinks a key is still in the cylinder and therefore unlocks the doors.

Let's hope cleaning the door latches solves your issues for awhile. If you used a penetrating oil rather than an electrical parts cleaner though, I wouldn't predict this to be a long-term fix though. Others on this forum will disagree with me on this point though and have had good results using WD-40 or similar. I prefer electrical parts cleaner though.

-Rod

[Grebus1]

Thanks for another excellent reply Rod. Since I originally posted, the doors opened themselves one more time, and then remained locked for the next 36 hours or so. I've been away from home since Saturday morning, so I'm not sure if they've remained locked after that (I hope so). I'm hoping it had something to do with the cold weather and won't continue to be a problem. I also thought about the key warning, but the power locks are continuing to try to unlock even when they are already open, not just when I hit the lock button.

By the way, can you tell me which particular fuse controls the door locks and the other functions you mentioned? I was not able to find the info in my owner's manual or the Chilton manual. Thanks again...

[shorod]

The power locks receive their power from Fuse #4 (30 amp) in the engine compartment Fuse/Relay box. There are also a couple of relays for the power door locks which should not be overlooked. The all lock and all unlock relays are located in the instrument panel to the right of the steering column.

The GEM module controls a lot of functions and I would not suggest removing power from it. The GEM module is sandwiched between the floor and the instrument panel fuse box.

What are the chances you have access to a datalogger or oscilloscope/DMM with glitch capture capability? It would be interesting to monitor a few signals in the car to see if the GEM is sending an unlock signal to the relay or if the relay is just unlocking the doors on its own.


-Rod

[medicmandan]

I have the opposite problem in my 99 Taurus. My automatic locks will sometimes lock themselves if the car is running and I get in and close the door. Wonder if it is the same issue, just a different result.

[Grebus1]

Well, so far the problem seems to have at least lessened. After I got home from the weekend away, the doors were unlocked. Since then I have been driving it daily and have yet to have them unlock on their own. Unfortunately I don't have access to the equipment Rod talked about, so I can't do that type of test. I guess I will just keep an eye on it and keep important stuff out of the car when it's parked. I was glad to find a lock on the glove box so at least that's something I can secure. Thanks again...

[cardkleener]

I have a 98 Taurus Wagon. I had the problem of doors not locking while driving and interior light staying on along with the door ajar light staying on. The solution was to spray the door locks with WD40. One of the forums said to use a spray other than WD40 but it was all I had. That was 1 1/2 years ago and I have yet to have the problem again.