[Hello, I my 1997 Montero SR 3.5 L has a didfferent engine nomenclature than the 96 and 98-99 but definitely later models. I've been told by some mexhanics model years may share the same part numbers? Can you confirm or shed some light.

I'm asking because I read positive review so the Montero's in general. However, I need suspension work, timing belt and tune up services. I would like to keep for a winter truck but the estimated costs of repairs is $$$$$ to say the least.

Acinc8020

QUOTE=jrmdir;14769]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[/QUOTE]

 

Thanks so much jrmdir for your ideas, i'll make it my next project!