Locking problem back..in spades!

[Paul in NZ]

A short time ago my car automatically locked itself immediately after unlocking.After cycling the drivers door lock a few times the problem went away but has now returned.The car locks itself,sometimes double locks itself.The drivers knob now stays down all the time,of course when the wife had the car.I havent been able to get the driversdoor unlocked at all today,its double locked.Its definetly the drivers actuator or switches.The car unlocks perfectly from boot and passengers side.Tomorrow will try climbing in and winding down windows and pull up on drivers knob whilst unlocking,then remove door panel.

[Paul in NZ]

update.....
ok I got in the passengers door after a brief attempt at the "emergency unlock" on the drivers door(rhd remember) and lowered the drivers window.I then got out and tried to unlock the car,first attempt always relocks instantly second attempt stays unlocked but the drivers door stays double locked.I then unlock the car applying upward pressure on the drivers knob,nothing but a slight downward tug as it relocks.I notice during the locking and unlocking that the alarm led never comes on and the passengers door handle does not actuate interior lights.The double lock function still closes the windows,and boot operates the central locking,car always relocks on first unlock.
I give the drivers door a shove and a slight click is heard.The door knob now responds to the lock but relocks instantly
So with the drivers door finally open I check the tiny switches at the door latches.The drivers switch is gritty and does not move freely,so a clean and a quick spay of crc and reclean,switch now moves more freely,repaet on passengers door.Locking and unlocking now normal!!

[Javier]

is the one associated with the key cylinder? As if you had a lock request permanently activated.

Javier

[Paul in NZ]

not sure Javier,but i havent fixed it,it did it again today.I seem to free up the culprit by "knocking" on the drivers door,something is loose in there.I hope it holds till the weekend!

[Javier]

to be causing this behavior, is the micro switch following the Key cylinder in the door handle. (One each front door). You seem to have located it to the driver's door.

I would guess it is this micro switch, that is either loose or wore out, and is closing the "Lock request" circuit, so the system behaves as if you have a key inserted in driver's door, and turned to the Lock position "permanently" (though the contact may be closing depending on the temperature, shaking, and other factors).

When the bug is in effect, no mater what you do with the system, the last order would ever be "Lock". Also, if you operate the drivers door to "unlock", with this bug in effect, it will act as a central arrest order (Double lock).

The only way I can figure out to confirm this hypothesis, is to check continuity on the switch wires wile the bug is in effect (Or to temporarily disconnect the lock cylinder in drivers door to confirm the bug went way, but you will not be able to use the key in drivers door).

Check your mail.

Javier

[Paul in NZ]

yes at its worst when i try to open the car the drivers door stays "double locked"I may remove drivers door panel and go around for a few days with the digital mulimeter.It means i will have to climb in passengers side to test it,but hopefully i will be able to check some theories abd throw some light onto a common problem.Will read my mail now!

[Javier]

any attempt to open the car at either door, should issue a double lock command to the GM (it is funny, but unlock at any door, together with lock at any door means double lock to the GM).

Mine is 92, so can not verify, it is different wiring, I understand that from 92 up, the door key operates the lock mechanically, and the knob position is monitored to issue a GM command to the rest of the doors. The only electrically issued command trough the keys, is the Central arrest (Double lock).

May be it will be easier to disconnect the lock cylinder micro switch electrical connector, and try the key at passenger's side, if the short/connection is inside the micro switch, either because it is loose, or wore out, the system should operate normally from passenger's door.

Javier

[Paul in NZ]

aha,we may be onto it.I discovered today that the car only misbehaves(lately) if i double lock it.Then when i unlock the car locks immediately.I unlock again the car unlocks but drivers knob stays down and cannot be lifted.Will keep my eye on it.If the microswith is disconnected on the drivers side will make the drivers side locking/ unlocking inoperative?

[Javier]

my guess on the key micro switch origin of the fault. May be the issue is in the actuator itself, a sticky actuator? hardware need a lube? Actuator can not complete the unlock because the central arrest is not removed, leaving the knob down, may be even after a brief pop up attempt, and the knob is the one issuing a lock command (just like it does when you push it down). This may explain why exercising it finally pop up the knob.

If you disconnect the wires to the Key Cylinder Micro Switch, the lock will work, but not the key, all doors will operate at passengers door commands, but I discarded the Key micro switch based in your observation on the double lock (Central arrest) contribution.

Javier

[RockJock]

the temperature around here is starting to drop once again (0 to a balmy 10 degrees C) and my door locks are starting to drive me nuts. here's what happens: i can unlock my doors using the key (from the DS, PS or the trunk). as soon as i pull the DS handle and pull the door open the doors re-lock. on occasion the doors will lock as soon as i shut the DS door. any advice or recommendations would be appreciated ....
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1989 535iM (242K km)