The power locks on my 95 Montero have been acting like maybe something is binding somewhere. If I walk up to the drivers door and insert my key and unlock twice to unlock all doors,.....it generally will immediately pop all the locks back down again. Does the same thing when unlocking the passenger side door or if I am driving the truck, and as I am getting out,.....if I hit the unlock button on the drivers door arm rest,.....it generally will rebound immediately and lock all the doors,.....a very bad thing if I have left the keys in the ignition and already slammed the door shut.................luckily, it has not happened yet.

Anyone experienced this and if so.........any suggestions on how to fix it??

Brian Collins

 

Brian:

I had the exact same problem with my 1999 Montero at around 75,000 miles and finally fixed it after weeks of trial and error. You could have a completely different problem since yours is a '95, but here's what I found:

It turned out that the problem was in the driver's side door lock solenoid (actually it's a motor drive unit) located inside the door near the bottom rear corner. This can be confirmed by unplugging the wiring harness at the motor drive and then operating the locks from one of the door switches. If the locks in the other three doors now work properly then your problem may very well be the same as mine.

I had three choices - buy a new motor unit from a dealer for something like $189.00, get a used one from a wrecking yard for $50, or tear mine apart to invesitgate. Note that the wrecking yards I called reported that all their full size Monteros were already missing the driver's side unit, so I figured I was on the right track. I don't know how mechanically adventuresome you are but here's what I did - procceed at your own risk.

Removing the unit was fairly easy, but it looked like the sides of the black plastic case were solvent welded together. However, they really weren't and with a pocket knife and small screwdriver I was able to pry off the back cover with no damage to the case. Once inside, I noted that there is a pie shaped cam that rotates back and forth when the operating shaft is actuated to lock and unlock. This cam swings back and forth through through an arc of about 110 degrees. At either end of this arc, the outer sides of the pie-shaped cam run into bosses molded into the case. These act as stops to limit the travel of the cam (and of the operating rod that locks and unlocks the driver's door.) In order to cushion things when the cam hit each stop, there are two small rubber bumpers about 3/16" thick that are snapped into the case on either side. The first thing I noticed was that one of these bumpers (the one on the "unlock" side of the cam,) was completely smashed and nearly disintegrated. The other one looked brand new. Next I noticed that as the cam swings back and forth, it also actuates small micro switches inside the case. These switches tell the control unit when the cam has traveled to the end of it's range and also let the controller know whether the cam (and thus the lock) is resting in the locked or unlocked position.

What seemed to be happening in my case is what without the 3/16" bumper on the unlock side, the cam moved just that much closer to the edge of the case and this allowed it to lose contact with the microswitch. Thus when I hit UNLOCK, the cam rotated too far since there was no rubber bumper. Along the way it closed the microswitch telling the controller it was in the unlock position, but then it lost contact with the switch and the contoller was somehow fooled into thinking that the command it was still receiving was a LOCK command. Of course when it then goes back to the LOCK side, everything works fine and that's where it stays.

The good news in all this is that the rubber bumpers are identical and can easily be swapped. Even better is the fact that it was OK in my case to leave the smashed bumper on the LOCK side. I think the reason my original lock side bumper was still in new condition is that the cam never really hits that side of the case - when the lock command is given, it appears that the rotation of the cam is stopped somewhere else in the lock mechanism - not by hitting the bumper.

In any case, after swapping bumpers and reassembling the case with a few dabs of super glue for good measure, my locks have been working fine ever since. And it all cost me not a cent.

Hope this helps.

jrmdir

 

Door Lock Actautor is your culprit!!1

 

Thanks JRMDIR for the excellent write up. I will make it my next montero task after I get new bulbs in my radio display.

Brian

 

love the write up. can't wait to fix this myself!!!!!!

 

Ron:

Thanks for your comment - it's fun to write about projects that turn out OK - not all of mine do.

I hope the fix works for your Montero - let me know. By the way, mine now has 132K and the locks have worked perfectly ever since.

Ron

 

jrmdir,

I realize that the post is quite dated, but information provided is priceless. I just finished fixing the problems on my 98 Montero and works like a charm. Although, both of my 'bumpers' where completely thrashed. I was able to figure which side needed the bumper and lodge a small piece of plastic in the area. I used some of the adhesive (from the plastic covering on the inner door) to hold it in place and viola, a perfectly working actuator. Many many thanks for the info.

delahuerta

 

Delahuerta:

Thanks for taking time to give feedback -glad you got positive results. My car is now at
190K and still no relapse. I hope the black "tar" from your door liner holds up as your glue but if not it will be easy to re-do. I like stuff called "Plumbers Goop" for gluing things like that.

Cheers,

Ron

 

jrmdir,
A thousand thanks for the detailed write up for the door lock problem.
I own a ’95 Montero LS and this problem reared it’s ugly head about a week ago.
I followed your fix and it was exactly the problem I had.
The unlock bumper was completely destroyed so I swapped it with the lock bumper and it now works perfect.
Thanks again for the fix.
Ron

 

Glad it helped another victim of the posessed door lock syndrome.

Thanks for taking the time to let me know!

Ron