I guess most people use the electric button to open up their boot (trunk), and maybe even miss that there's a keyhole as well. To avoid future headache, I suggest that everyone checks if they still can open with a key.

On my car, the lock was completely jammed, and I panicked a bit when I first noticed that the battery was flat and the key wasn't working. I solved this by putting jumper cables to a connector close to the engine, but decided that I shouldn't need to do that if the same thing happens again.

First, I removed the lock from the inside of the lid. On my X308, it was held by two 10 mm nuts, and a plastic clip going to the latch. The lock is made up of three separate parts, and there's also a small spring, so be careful not to lose anything.

With the lock removed, I drowned it in WD40 and left it overnight, which didn't seem to work at all. I sprayed some more WD40, put the lock in a vice, and took an 8 mm spanner to the inside of the lock. I kept the key inside the lock at all time, and after some twisting the lock started working. With the lock all oiled up, I put it back in the car, and I will try to use it a bit more often now.

Thankfully mine works...but if I run into that issue, I will be sure to follow these steps

Thanks for the tips, good info and advice to check and exercise that lock as most folks indeed probably only open their trunk with the key fob, inside button or occasionally the electric button under the 'growler' on the lid itself.

Funny thing about that outside electric button is that we've found that a lot of owners don't even know that button exists and just think it is simply the 'growler' emblem. As such the micro switch under the emblem often goes bad (at least on X300 models) from disuse or weather.

BTW, not to pick, but WD40 is not really a very good solvent or lubricant (even though they market it as such, but look up its history) and can end up gumming up precision devices such as a lock. Most locks don't respond well to generic oils or the wrong kind of lubricant.

Once the lock is cleaned with an appropriate solvent, one should use a lubricant made for locks, which often is something dry like graphite. If unsure, calling a local locksmith or maybe even the dealer can help identify what type of lubricant to use.


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Thanks for the tips, four!

+1 on dry graphite and +1,000 on Al's comments about WD40. It's primarily a solvent that leaves behind very little lubricant, but just enough to attract and trap dust that will eventually gum up the lock again.

Cheers,

Don

Well, I have the exact opposite issue, the key lock works fine, but the button inside the car, as well as the button on the boot lid AND the fob do not work. Haha

That's a fractured wiring issue - you'll need to do the following
remove the trunk carpet and i.d. the colour of the feeds to the lock mech also remove the r.h. hinge cover to expose the trunk panel harness...
remove the wiring harness tape and inspect the wire leading to the trunk lock, it will be the lock motor feed, it sounds like it's broke, usually at the hinge.
The open/close action work hardens the copper wires over a long time and they break
fix the break with solder and shrinktube and all should be well again - this is a common issue.

Can confirm SeanB's comment. I am not a very handy man, but I just today fixed my similar issue. Dash button worked but gave up, keyfob worked but gave up, growler button never worked. Searching this forum gave good information with pictures and procedure, just like SeanB's. Three wires was cut right off and two more "dodgy". You can feel along the wires to identify bends or wear.

For the first time I welded and shrink wrapped five wires. A bit tedious for a first timer, but everything worked after an hour and a half labour. And this for a complete novice. (I was about to order a new microswitch ++, research on this site makes wonders and saves $$:-)

My point being; there are so much help to get from this forum and don't be afraid to try. Thanks to all posters and the competency you have.

thanks. good info

I tend to use the key fob more because if The Duchess is locked, keying the trunk will activate the alarm. Having checked
that all is well with the key lock mechanism, is a positive to be sure. One never knows when the battery may become
so old or discharged that the electro-mechanical solution will fail, leaving the mechanical as the only choice to acquire
access to the battery compartment.

That happened to me yesterday. Battery Cable was slightly lose so had to jump start at battery cable under hood.

On my son's 99 XJ, someone must have slammed the trunk which cut through six wires in the back of the hinge. ( It was like this when he bought the car.) The button and garage opener did not work nor the interior trunk lights. Soldering them fixed it all.

+1 to the fact that WD-40 is not a lubricant.
Also, be careful with dry lubes like graphite in humid environs like southern Louisiana. It will end up pasty and minimize the lubricating factors. I suggest flushing the lock with WD-40 and then applying something like Tri-Flow which has all kinds of lubricationators and will help clean the lock further.

Thanks. Thats what I will do.

Where do you put the 8mm spanner?

Probably on the key.

After first summer I owned my car I realized this same thing. I had to get the lock working because I was going to put the car away for the winter and going to disconnect battery cable. And of course closing the boot lid. Lock mechanism was completely jammed. But taking it all apart one by one I managed to free up all of the key fins (whatever them discs are in english what follows the key shape). Putting it back with a loads of ptfe grease and keeping it greased after every wash it has been working very well ever since.

If you get tired of trying to free up your lock just leave the roll pin out. Works great then and key turns 45 degrees.
No more then I will be using it im happy with this method. Works great. (Not for the purest )

Actually you can jump start the car under the hood (bonnet) at the battery cable

Yes, assuming one has access to "under the hood" then a battery charger can be used to momentarily apply
12 volts to the bus bar in the fuse box and ground to any bolt on the chassis / bodywork in the engine bay.
At that point the trunk can be opened by use of the key fob or cabin trunk switch. However, it is so much
simpler to just have a working trunk latch.