1997 Taurus Wagon Power Door Lock Problem

Hello,
the power door lock in the rear of my Taurus wagon by the CD player will not operate.

I have tested the switch and do not believe that is the problem.
power locks switches on the other doors operate. push button keyless entry works also.

I am thinking it might be a problem with the door lock switch motor behind the lift gate moulding? I believe there is such a thing

If the liftgate is up, and I lock the doors, when I put the liftgate down, the anti-theft system actuates and the horn goes off....etc....

I would appreciate any ideas anyone might have!

thank you!!

I'm not clear on the problem. Does the rear liftgate not lock when you press the door lock buttons, or does the rear door lock switch not lock the rear liftgate?

Does the liftgate lock work when the liftgate is open but not when closed? If this is the case, there's a good chance that one of the wires that goes through the wiring harness into the liftgate is broken inside the wire insulation and makes contact when the door is open (wire compressed) but not when the liftgate is closed (wire stretched). Didn't you experience something similar to this on the same car with the rear wiper/wiper motor?

-Rod

Sounds like the poster is saying when he pushes the door lock button in the cargo area, the other locks work, but not the liftgate lock. I think this is how the switch was tested.

Don't know why the anti-theft system would go off if one of the five locks was in a different state from the other four.

I guess I would suspect the actuator for that lock inside the liftgate. I'd be testing for power from the switch at the actuator.

I've got a '97 Taurus Wagon and even though I've replaced one window motor, all my door locks still work (160k). One thing I've noticed about my car, however, is that the locks have never automatically locked once the car is put into gear. I've always thought they were supposed to do this (I think I even checked the owner's manual at one point to confirm), yet they don't work that way.

One thing I've noticed about my car, however, is that the locks have never automatically locked once the car is put into gear. I've always thought they were supposed to do this (I think I even checked the owner's manual at one point to confirm), yet they don't work that way.

I remember seeing in the owner's manual for the sedan that the owner can enable or disable this feature through a sequence of key cycles and lock applications or something. Maybe it's been disabled on your car and the owner's manual may walk you through the steps to turn it on if it's important to you.

-Rod

Yeah - you're right ... it was some goofy sequence thing like that. I remember attempting to try it a few years ago but there was something about it that didn't make sense for my model. IIRC, the sequence was written for the more upscale model. I don't think I had the necessary buttons to do the sequence (or something like that).

I'll have to look that up again...

Owner's Manual says AutoLock is part of the remote keyless entry system - which my car does not have. Deactivation is accomplished by one of two methods - pressing a button sequence on the door handle keypad (in a timed fashion), or performing another (lengthy) sequence using the door lock button and ignition key position (but this requires presence of the anti-theft system) - which my car does not have, either.

Hello Fellas,
thanks very much for your reply!
sorry it took me so long to get back to you...
to answer your questions, when I push the liftgate lock switch by the cd player, nothing happens.
when I push the door lock switch on either front door, all five doors lock.
this seems to isolate the problem to the liftgate lock switch and/or associated wiring.
I have a Helm manual and I have tested the switch and it has continuity...so it does not seem to me that it is the switch.
I have tested the three leads for voltage with a multi-meter(I don't know completely what I am doing) and I seem to have some voltage which I believe you would expect as the lock switches are live all the time.
I then reached for my 12 volt test light. I grounded it to a bolt on the frame and touched the probe to the points on the back of wiring on the switch...lo and behold all doors unlocked and locked.
this leads me to believe I have a problem with a ground wire?
what do you think?

I believe the door lock system is tied to the anti-theft mechanism, which is why it goes off during the conditions I mentioned.....

thank you again!

Hello Rod,
to answer your other question...sorry I missed it....
many moons ago, I had a problem with the rear window defroster and the rear wiper on the liftgate. When something doesn't work correctly..it gets my goat.......Took me a long time to figure it out. I did find several...2 or 3 broken wires in the rubber boot that goes from the frame of the vehicle into the liftgate frame. What a pain to repair...I fixed them and those components have worked ever since...
I think this particular problem with the door lock switch is different....The liftgate lock does work when the power door locks on either of the front doors is pressed.
thanks again!

According to the factory service manual door lock wiring diagram for the wagon, the tan/light green wire from the switch goes to a diode in the diode center which prevents the switch from backfeeding the Generic Electronic Module (GEM). The cathode of the diode is connected to the GEM at a splice shared with the liftgate window ajar switch as well as the liftgate door ajar switch. Both switches are in series between the GEM splice and ground, and the two switches are in parallel with each other.

So it would seem from the diagram that the rear lock switch will only work if the diode is good and at least one of the switches is closed. Since you mention that closing the liftgate will cause the alarm to go off, I suspect you may have a faulty liftgate window ajar switch that is sticking open and therefore, when the liftgate door is open to try the lock button, both switches are reading open. When you close the liftgate door, the alarm arms then triggers because of the open window switch. Or maybe the act of closing the liftgate door causes the liftgate window switch to bounce, triggering the alarm.

I'd suggest you try the switch with the liftgate door closed and the liftgate window open. If that works, then you can rule out a wiring issue for the switch.

-Rod

Hello Rod,
thank you very much for your response.
you are a very sharp individual.
I tried your suggestion.
you were correct...with the liftgate closed, and the window open, the door switch will lock all five doors.
just for clarity for me, would you suggest replacing the window ajar switch? or maybe both of them?
it is a bit of pain to pull the door panels off...you ruin the plastic holders...crack the points on the door panel that hold the little plastic pieces...etc......anyway....
thanks again!