Disable internal keyboard on high sierra
I assume you're talking about some sort of MacBook model. I would reset the Non-Volatile Random-Access Memory (NVRAM) to see if that resolves things for you.

Resetting the NVRAM

You don't specify your specific Mac model, so these generic instructions should cover all Macs (except for the iMac Pro which I'm assuming you do not have). Follow these steps: 


Shut down your machine. Yes, a full shut down, not just logging out.
Press the power button and then immediately press the commandoptionpr keys. 
Keep these keys pressed down for at least 20 seconds!
Let go of the keys and let your Mac reboot normally.


Notes: 


Do not be concerned if your Mac appears to restart during the 20 second period.
When you log back in you may need to readjust some of your system preferences (e.g. speaker volume, screen resolution, startup disk selection, time zone information, etc).
If the problem is still present after you've rebooted, then proceed to resetting the System Management Controller (SMC) below.


Resetting the SMC

As you haven't specified your specific Mac model, these instructions apply to all MacBook models on which you cannot remove the battery (i.e. it's a built-in battery). If you have an older MacBook model or a desktop Mac, please refer instead to How to reset the System Management Controller (SMC) on your Mac. Otherwise proceed as follows:


Shut down your Mac
Unplug the power cable from your Mac
For 10 seconds, press and hold at the same time the shiftcontroloption keys (on the left side of the built-in keyboard) and the power button
After 10 seconds let go of all keys and the power button 
Plug in the power cable
Turn your Mac back on with the power button.