eccola:
Open up this page, BitAddress.org, and LiteAddress.org
Disconnect your internet.
Type in your ledger seed into the "BIP39 Mnemonic" field on the first page.
Select the BIP 49 tab at the bottom.
Find 3PXCdYCABF9CDfHkKCcxJbqNiS9jhYcfqP on the list.
Copy the private key into the Wallet Details tab on BitAddress.org. Scroll to the bottom and copy the "Private Key Hexadecimal Format (64 characters [0-9A-F]):" value.
Go to the LiteAddress.org page and move your mouse until the Wallet Details tab appears. Put in the hex key from the previous step in here.
Select and copy the compressed WIF key (NOT the one starting with 6). Also, keep note of the "Litecoin Address Compressed" from the first half of the page (starting with L)
Open up Litecoin-qt, then head into the debug console.
Run importprivkey "<the Litecion Compressed WIF>" (with quotes).
Once the import finished, run addwitnessaddress "<the compressed Litecoin address starting with L that you selected earlier>".
Wait for this import to finish as well. Take the M-address from the console and use this tool to convert it to a 3-Address. Verify that it matches 3PXCdYCABF9CDfHkKCcxJbqNiS9jhYcfqP.
If the funds haven't shown up yet, close Litecoin-qt.
Restart Litecoin-qt along with a rescan. This varies by OS, and in most cases will happen automatically if you wait for 10 minutes or so before restarting.
In case your rescan doesn't start automatically, try one of these.
If you're on Linux:
<path-to-Litecoin-qt> -rescan in a terminal
If you're on Windows, create a shortcut to the Litecoin-qt application, right click, edit the properties, and add -rescan to the end of the target.
If you're on OS X, run <path_to_Litecoin-qt.app>/Litecoin-Qt.app/Contents/MacOS/Litecoin-qt -rescan in a terminal
Remember to make sure your Litecoin-qt is fully synced before rescanning. If it isn't, you'll have to wait for it to sync, and then rescan again.
Please feel free to reach out if you need any help with any step!
