Nissan Repair: power locks, nissan pathfinder, debouncing

Question
Hello, I have a 1995 Nissan Pathfinder SE with power door locks.
I just recently purchased it used and it seems in good condition
as far as the engine is concerned. The only bug I have noticed in
about 500 miles of driving is the locks enagage and disengage
randomely while the car is on. Also the keyless entry remotes
don't seem to be working, even after I replaced batteries. Is this
a common problem that can easily be fixed by me or should I
take this in to a repair shop? Just wondering if there are some
things I can check before I take it in?
Thanks for your help.


Answer
Baldomero,

I took this writeup from a Quest/Villager site and it shows all the issues with your year model on the door locks.

  1.  Lack of debouncing of the switch on the manual door lock
  2. Corroded power feed near the battery
  3. Flaky power smart entry controller
  4. A Pinched wire


1.  Noisy Door Lock Switches/Lack of debouncing on the door lock switches  I would expect the Smart Entry controller to have some amount of switch contact debouncing built in, but apparently there is none or inadequate debouncing of the switch contacts. What this means is that if for some reason the switch contacts are broken for a broken at any brief moment the controller thinks that you have activated the door locks through the manual door locks. The switch contacts can be disturbed causing this momentary break through a vibration like opening one of the doors. In my case, the door locks would often activate when we were opening the passenger side front door. Here is fix from Steve Cutchen who fixed his door lock problem by the following:

I traced the problem to something in the driver's side door mechanical keylock... the literal part inside the door at the keyhole. When locking the driver's side door lock from outside with the key, all of the other doors lock as well. The electrical contact that signals the power locks from the keylock was evidently activating some of the times when the door closed. Mechanically something inside the lock assembly was making the electrical connection when jarred. The proper solution was probably to replace the lock assembly. But that wasn't my solution. I have remote operated locks that came with my alarm system. So I never use the keyhole lock, much less the "lock the other doors for me" feature. What I did was cut the wire, disabling all electrical connection between the key lock mechanism and the power locks. On my '93 Villager there is a green/red stripe wire which goes from the door lock actuator assembly to power door lock module (or the keyless entry module, if you have that). (the modules are in the center console area...) I cut this wire inside the driver's door. I then twisted on a small wire nut on the end coming from the power door lock module to keep the wire from contacting a ground.

If you find that your wire colors do not match you can cut either one of the smaller gauge wires.  There are four wires on the door lock actuator, two to power the actuator mechanism, and two to signal the door lock controller the state of the door lock.  Do not cut the heavier gauge wires.  Those are the wires that power the actuator.  When cutting the wires, make sure that you leave enough wire on each end so that the wire may spliced back together if necessary. There is a module near the latch inside the door. This is the location of the wiring that you need to gain access to in order to modify the wiring.

Here's the description from the shop manual on how to remove the door panel...

  1. Remove the door latch handle trim.
  2. Slip a clean shop rag between the window crank handle and the front door trim panel, if equipped. Pull the shop rag back and forth to release the window crank handle clip
  3. Remove the two cover caps and front door trim panel screws.
  4. Remove the two front door trim panel capped screws.
  5. Pull out on the panel beginning at a bottom corner to release the plastic push-pin clips.
  6. Pull up on the front door trim panel from the top to release it from the door panel
  7. Disconnect the door lock/unlock switch and power window switch electrical connectors, if equipped.
  8. You now own the front door trim panel.


To install, reverse the removal procedure.

Once you get the panel off, you'll find a thin water shield held in place on the door by a rubber adhesive. Carefully pull the shield away from the door without tearing it. You'll be able to just stick it back to the existing rubber adhesive... it stays tacky.


2.  Corroded Power Feed  I have had at least two reports from people who have had problems with corrosion of the power feeds near the battery. There is one large gauge wire that feeds the starter and two smaller gauge wires that feed power to other things. One person reported to me that one of these power feeds was corroded so bad that it would sometimes cause the power door lock controller to lose power and then regain power. This power glitch would cause the power door locks to activate. The fix is to repair the corroded power feed near the battery. The reports of this problem have all come from the owners of '97 models.

3.  Flaky Power Door Lock Controller  I have had a few people complain to me that their remote keyless entry seems to be locking the doors on its own. This is often characterized by the confirmation honk from the horn like when using the remote keyless entry. Apparently the controller is receiving some phantom signals indicating to it to lock the doors. The only fix I can think of is to replace the keyless entry controller. Some people have just disconnected the connection of between the doorlock controller and the horn in order to suppress random horn honks coming from their van.

4.  Pinched wire  The pinched wire fix is fromTom in Indiana.

I just repaired the problem on my '93 Villager, and it was caused when the wiring harness to the driver's side door manual lock was pinched between the interior door panel and some metal part inside the door. The insulation wore through and was grounding the circuit against the metal part. I just taped over the small opening in the worn insulation and relocated the harness away from the source of friction that wore it through in the first place.