Door won't lock

[m1santhrope]

Hello, I've been working my way through a list of issues and have reached a problem I've inherited with the rear near side door lock.

Four of the five locks work on central locking, I have removed the trim and tested voltage on the actuator connector. My initial instinct is to try and find a new motor but I'm wondering if it could be down to the mechanical linkage.

Problem is I'm having trouble fault finding as I do not understand how this mechanism should work.

[Laird Scooby]

Originally Posted by m1santhrope

Hello, I've been working my way through a list of issues and have reached a problem I've inherited with the rear near side door lock.

Four of the five locks work on central locking, I have removed the trim and tested voltage on the actuator connector. My initial instinct is to try and find a new motor but I'm wondering if it could be down to the mechanical linkage.

Problem is I'm having trouble fault finding as I do not understand how this mechanism should work.

Use a small (5W ish) 12V test lamp across the wires that feed the lock motor/actuator to see if it's actually getting the lock/unlock signals. The lamp will light for ~0.5-1.0 second for either signal. If it does, lube the latch and the mechanism and operate it manually several times then try again on the central locking, assisting it if necessary. Could simply be stuck from lack of use.

If it appears the actuator is dead, contact Luke aka 360beast as he often has a few breakers in and keeps a few bits and pieces handy even when he doesn't have anything in for breaking.

[m1santhrope]

I have had a multimeter on hold peak function so i know there is a voltage signal during lock and unlock.

I will lubricate the mechanism, please can you advise how i would operate manually, is it moving the horizontal steel rod up and down?

[Laird Scooby]

Originally Posted by m1santhrope

I have had a multimeter on hold peak function so i know there is a voltage signal during lock and unlock.

I will lubricate the mechanism, please can you advise how i would operate manually, is it moving the horizontal steel rod up and down?

Use a test lamp as described. A multimeter is no good for this test.

Depress the lock button to lock, lift the door release handle to unlock. You will need to fool the latch by moving it into the shut position with a screwdriver blade or similar to simulate the door being shut.

[m1santhrope]

I forgot how the lock mechanism worked, but childhood memories are coming back now.

I can lock the door manually while grabbing the door release then pushing the button, I’d forgotten this.

When i try this on other doors i can manually lock a door, the door in question will not let me push the internal button down even when grabbing the door release. So could be mechanical issue...

[loki_the_glt]

Originally Posted by m1santhrope

I forgot how the lock mechanism worked, but childhood memories are coming back now.

I can only lock the door manually while grabbing the external handle latch then pushing the button, I’d forgotten this.

When i try this on others doors i can manually lock a door, the door in question will not let me push the internal button down even when grabbing the handle latch. So could be mechanical issue...

Take off the trim panel on the other rear door and compare the two linkages; almost certainly something has jumped/fallen out or jammed, and f this is the easiest way to check.

[Laird Scooby]

Originally Posted by m1santhrope

I forgot how the lock mechanism worked, but childhood memories are coming back now.

I can lock the door manually while grabbing the door release then pushing the button, I’d forgotten this.

When i try this on other doors i can manually lock a door, the door in question will not let me push the internal button down even when grabbing the door release. So could be mechanical issue...

Don't grab the handle, it shouldn't be necessary on a rear door. Fool the latch by moving it with a screwdriver to replicate the striker pin moving through the latch to the closed position (NOTE 2 positions, first is not fully shut, the second click is the one you need.) and then operate the lock button etc.

If i've understood your last paragraph correctly then assuming you've fooled the latch as described above, it would be fair to assume something is either out of place as Loki suggests or something has siezed within the latch.

[m1santhrope]

Ive compared it with the opposite door and first thing i noticed was the horizontal rod to the button was bent near the actuator. That is a symptom rather than a cause, like someone has tried to force the button down.

I can manually lift and push all other door mechanisms above the actuator the inch or so needed to open and lock each mechanism. The faulty door lock is stuck in one position and no force up or down will click the door.

I think the lock may be seized open, unfortunately i can only remove one of the Torx screws so thats it for today...