Boot lock freezing up??

[widdershins]

Hopefully someone will know the answer to this. 

 

First the background.  The last couple of days here in Scotland have been a bit snowy and chilly (-15C last night!) and my facelifted Yeti has been living outside.  So today I had to go in to work and set off whilst it was still pretty chilly.  Had the heater on and it was toasty inside by the time I arrived.  However by the time I was ready to head home the temp was -7.5C.

 

Now to the problem, I had a replacement monitor to lug home from work and wanted to put it in the boot for safety.  Pressed the button to unlock the doors and boot on the fob and the car unlocks and the usual sounds of deadlocks retracting.  So far so good.  Walked up to the boot and pulled the catch, usual whirring sound of solenoid or whatever, but zero movement from the door.  Now,  I mean absolute zero movement, it wasn't a feel like the rubber seal was sticking and holding the tailgate shut, that would have some give as the rubber seal flexed.  This felt as though it was still locked.  Tried the little button beside the gear stick to unlock all the doors in case it was the fob playing up since the battery must be ancient by now, but still nothing.

 

So I give up as it was blooming cold and there's a icy wind cutting through me, stuff the monitor into the passenger footwell, de-ice the windows and head home.  Heater is on, and thanks to roadworks I have a detour before I can join the motorway.  This turns out to be very fortunate as the dashboard shows a warning that the boot is open. Just before the motorway slip, if not for the roadworks Id've been doing 70 on the motorway at the time.  I pull over and try the boot latch again.  This time it opens about 1-2 inches, but no more.  I push it back down and it doesn't latch closed, pull it up harder, still just the same 1-2 inches no more.  Push down harder still not latching.  Repeat a couple of times, same result.  Try the little switch by the gear lever, no difference . 

 

Then in a moment of desperation I take the key and press the boot catch release only button on the key fob.  Success, the tailgate opens like normal, as though nothing had happened 

 

So I take my little mini mag light and inspect the latch and the pin, nothing jamming them that I can see, so slam the tailgate shut hard.  It locks, then I try the latch and now it opens as normal. no 1-2 inches only, no needing to use the boot release on the key fob, just normal operation.  

 

Has anyone come across this sort of thing before, and if so what was the solution.  My best guess is that something in the lock mechanism didn't like the unusually low temps and froze solid until the car warmed up enough to free it up.  If I'm right then why did the boot latch only button work and the others didn't?  Does it operate the release mechanism in a different way?  Also how do I prevent it happening again, is there something I should dismantle and grease within the locking mechanism?

 

Edited 11 February, 2021 by widdershins

[Urrell]

I suspect it was the door rubbers sticking and movement of the body when car moving flexed them enough to let door open against the first catch.

[gumdrop]

One of my first jobs in the winter is to wipe around the door rubbers with silicone spray,

then do the door locks with the same stuff (there may be something better for door locks)

Then connect up the CK battery charger if I'm not using the car regularly and muff up the

radiator grill. I used to park back end of the car into the wind where practicable, as well.

[freedie]

There is a method of opening the rear door from inside the car should it prove necessary.

Details will be in the manual. (I say that as I have had to try it out!)

[weasley]

If it helps, this is what it looks like inside. The white plastic lever is the emergency release.  The plastic shaft from the gear on the right can shear, leaving the unit unserviceable (this is what happened to mine).

[widdershins]

3 hours ago, Urrell said:

I suspect it was the door rubbers sticking and movement of the body when car moving flexed them enough to let door open against the first catch.

 

It didn't feel like that though, I've had that happen to the front doors occasionally and if the latch releases there's usually a tiny amount of movement as the stuck rubber flexes when you pull.  This felt like it was locked still. 

[widdershins]

32 minutes ago, weasley said:

If it helps, this is what it looks like inside. The white plastic lever is the emergency release.  The plastic shaft from the gear on the right can shear, leaving the unit unserviceable (this is what happened to mine).

 

Ah so that's what it looks like inside.  I'm guessing that the white bit rotates and that unblocks the black bit of the hook on the latch and it can swing round and open?  Perhaps there was frost/ice in the black hook bit of the latch mechanism holding it shut then.  If the white bit had sheared off it wouldn't have started working ok again afterwards would it?

[weasley]

It’s a screw-linear actuator- the motor turns the gear, which has a worm gear type of shaft, which moves the white plastic block up, which pushes on the latch to pop it open.  The motor only turns a few revs until the plastic block reaches the end of its travel. When power is released the mechanism rewinds back to the beginning.

 

The characteristic symptom of a failed unit is a ‘drilling’ sound when trying to use it, as the motor keeps spinning.

[weasley]

You can read about how I discovered all this here.

[widdershins]

Well there wasn't any sound of the motor running on, so I'm hoping it is nothing serious.  Once the weather warms up a bit I think I'll try to open it again and get some lube into the lock cam and also give the rubber seal some attention with some silicon spray.

 

Thanks for the link to that thread.  It has some useful info on part numbers, so if the lock is failing I'll at least know what part I'll need.

[J.R.]

15 hours ago, widdershins said:

 It locks, then I try the latch and now it opens as normal. no 1-2 inches only, no needing to use the boot release on the key fob, just normal operation. 

 

You made no mention of this, if this is what was happening then its clear what the problem was, if there was no movement then I am confused by why you wrote the above.

[widdershins]

Erm... I did make mention of it, in my initial post, the one you quoted.  The edit was only to correct a couple of spelling mistooks I only noticed after posting.

 

Initially when setting out on my trip home there was absolutely zero movement when trying to open the tailgate.  It was as though it was still locked, even though the sound of the latch actuator could be heard when the handle was pressed.

 

After driving for a little with the heating on the door open warning came up and on stopping to check it, the tailgate would open a little, but then stop.  When I tried the boot latch release on the fob it opened normally when I then tried opening it again.  Whether that was pure chance and something had thawed out a little more, or there was some reason the fob boot release button worked when the other buttons I didn't know.

 

Weasley's post of the mechanism would suggest that there are no other electrical connections, so the different button allowing it to open was pure chance.  

Edited 12 February, 2021 by widdershins

[J.R.]

Sorry, my mistake, I had skipped a paragraph.

[eribaMotters]

9 hours ago, gumdrop said:

One of my first jobs in the winter is to wipe around the door rubbers with silicone spray,

then do the door locks with the same stuff (there may be something better for door locks)

Then connect up the CK battery charger if I'm not using the car regularly and muff up the

radiator grill. I used to park back end of the car into the wind where practicable, as well.

Gumdrop,

totally agree with silicon on the door rubbers, talc is also good., but best to avoid silicon spray or even WD40 for that matter. Don't use anything wet. Best is Foliac, a carbon powder. Now my supply of this has gone I spray some ptfe onto my key, wait for the solvent to evaporate than slide the key into the lock. I recently had to do this on my "gritty" house front door lock and the transformation was amazing.

 

Colin

[gumdrop]

1 hour ago, eribaMotters said:

Gumdrop,

totally agree with silicon on the door rubbers, talc is also good., but best to avoid silicon spray or even WD40 for that matter. Don't use anything wet. Best is Foliac, a carbon powder. Now my supply of this has gone I spray some ptfe onto my key, wait for the solvent to evaporate than slide the key into the lock. I recently had to do this on my "gritty" house front door lock and the transformation was amazing.

 

Colin

Hello Colin, I use a "plumbers" ptfe silicone and put it on a cloth, you are correct a direct spray is "too wet"

[Llanigraham]

Lots of members have had excellent results using GummiPfledge on the door/hatch rubbers.
You will find many recommendations on this forum group.