Touch screen does not work

Check the connection between the display and mainboard.  Service manual:

https://www.dell.com/support/home/en-us/product-support/product/xps-13-9315-laptop/docs

@ejn63​ Thank you but a little more precise information would help.  I have tried everything listed on the troubleshooter without success  except reinstalling factory defaults.  I am travelling overseas and that is not an option until I get home.  Please, where can I access the connection?

Use the service manual to locate the instructions for removing the palmrest and display panel.

@ejn63​ I do not understand how that can solve the problem. The display screen can easily be disconnected from the keyboard/touchpad/palm rest unit.  Then I have a tablet(screen) without a keyboard.  Without the keyboard attached I have a useless doorstop because the touch screen does not work.  I need some advice on why my Dell tablet touch screen is not recognised.

@[DND] DELL Community​ 

Dell XPS 13 9315

Always had a touch screen but suddenly it is not recognised

In Tablet and PC Settings (not originally listed) "No Pen or Touch Input is available for this Display"

Not listed at all under Human Interface devices.

All Windows 11 updates are installed.

Dell troubleshooting does not identify the problem at all.

The key board and touch pad work properly.

The bottom line is that the Dell system does not recognise that there is a touch screen.

It is very inconvenient.

How do I get the Dell XPS to recognise the touch screen?

First, there are two 9315 models -- yours must be the 2-in-1, not the standard 9315.  Your question refers to the 9315, not the 2-in-1.

Check the pins and contacts on both the tablet and the case for damage, corrosion or anything that insulates one from the other.  Clean the pins and contacts.

If that doesn't solve the problem, one or the other -- the case probably being the first to try -- needs to be replaced, as there is no way to service either component if it isn't making good contact.

@ejn63​ Thank you. Yes it is a 2-in-1. That solution is not certain .  The touch screen should work without the case,  It is tablet after all. I will consider this further but it may be better to replace the machine with a Microsoft Surface - my previous one was  afar better machine,

Finally solved this.  A Dell technician spent a long time but it is actually very simple.

In my case under Device manager - Human Interface Devices both the touch screen and pen were not listed. 

Go to Bios Setup - Press start and tap continually on F2 until the Bios set-up appears

On left side tap on Display

See a switch that says Touch Screen On/Off 

Mine had been switched to Off by some unknown force

After changing it to On and rebooting - all good

Ran Dell updates and everything back to normal.