FN key "stuck" and non-responsive on my Lenovo ThinkPad T450

Question

My problem

The FN key on my Lenovo ThinkPad has been non-responsive since some time last year and is just showing this constant green light which never turn off except when the laptop is turned off. The cause of it getting "stuck" in such way is unknown, but I am almost certain it is not due to physical damage as everything else works perfectly fine.

(except my battery which may randomly switch states and turn my computer off at random times, but that's another issue.)

What I've tried

I have tried various solution on the internet, like for example trying different combinations also attempted to disable the FN key entirely but nothing works. I also tried contacting Lenovo and looked up on their forums, but it seems they only offer to replace the whole keyboard which is not an option for me.

It is quite frustrating as it stops me from controlling my volume from the keyboard or access other shortcuts which forces me to go out of my current session and do it manually.

If you need any additional information, I'll be happy to provide. I'm mainly looking for what the cause of this could be and hopefully a solution for this and if anyone else has experienced something similar before with Lenovo Thinkpads.

Thank you in advance, any help is much appreciated.

Solution 1

I am almost certain it is not due to physical damage as everything else works perfectly fine.

It is often the case that an accumulation of detritus or a drop of liquid affects one key without affecting others.

If you suspect a OS/driver software issue, simply booting from a "rescue" CD or USB drive will disprove that.

The operation of the FN key is likely to be handled in firmware (or, in legacy terms, BIOS). You could check that at power-up to see if there are any available settings that might affect the usage of the FN key.

My guess is a hardware issue: - spilled food or drink; dead insects; discarded staples, simple mechanical failure from impact or overuse or defect etc. As a first step, it should be simple to remove two keycaps and inspect, compare and clean the mechanism.

Solution 2

FN key “stuck” and non-responsive on my Lenovo ThinkPad T450

try this: Fn+ESC

Comments

[Moab]

" I am almost certain it is not due to physical damage" How do you know this? wishful thinking? If you want it fixed replace the keyboard.

[Sanguinary]

@Moab It is not wishful thinking, I'm being logical. And by replacing the keyboard is not going to "fix" my issue here. That's workaround the problem, not a fix. I'm trying to learn from what I might have done wrong to cause this issue in the first place.

[Sanguinary]

Even though this didn't fix my problem, it explained the reasons why. I may have hasted a little and I now believe my problem is due to a hardware failure in someway which answerer may have explained. I will not replace my keyboard, but I think this is the best answer to future visitors.

[Sanguinary]

My question states that the button is non-responsive. Why would you think pressing that combination will work?

[Eneroth3]

I had a problem with my CPU and after they switched the mainboard the function key did not work. They hoped to fix the issue with a new keyboard but the issue remained. So from my experience that this can be also a mainboard or related issue.

[questionto42standswithUkraine]

@Sanguinary is right. This will only lock / unlock the fn key. The asker will for sure have tried the function key both with and without the fn key. The anser is not helping here. And by the way, here is the reference to what is written in this answer, though it is not the answer to the question: If you have such issues of a constant fn-lock or unlock on a Lenovo, see support.lenovo.com/us/en/solutions/….