I have a 4 digit schlage keyless lock and want to reprogram it

Reset it to factory settings and then reprogram it

I do not believe you will be able to reprogram the lock without the programming code, usually found on the sticker (unreadable, in your case).
Therefore, I urge you to call Schlage directly-they may be able to help you. here is the contact information:
United States Customer Support
Warranty & Technical Information: 1.888.805.9837

You are right about the support link going 404-It used to work. Get there by going to:Schlage.com
and clicking on "For your home"
Mouse over the "Service & Support" link, then go down & left click on "Instruction & Manuals". There ya go!

According to the installation instructions, you should not have to reprogram the lock after changing batteries.
At any rate, here is a great link where you will find videos and instructions for Schlage locks:

This link will take you to the page you need, to get started:

http://consumer.schlage.com/Service-Support/Pages/InstructionandManuals.aspx

Then scroll down to this heading on that page:
Electronic Security-Keypad Deadbolt BE365
There's a wealth of info under that heading. You will be able to see a PDF file of the original print instructions, as well as a video of how to install the lock. This is useful because there should be a sticker to be found on the backside of the keypad, with the code number that you need to reprogram the lock. This installation video (second item down) will be useful to allow you to disassemble it and view the sticker. This is also a great time to change the 9-volt battery!
The seventh item under that same header is a video which walks you through how to reprogram the keypad to your new code, using that program code that you found on the backside of the keypad.

Good luck!

Does the Schlage Keypad Lock or Keypad Deadbolt need to be reprogrammed after changing the battery? The Schlage Keypad Lock and Keypad Deadbolt does not need to be reprogrammed after replacing the battery. All settings are retained in the memory of the lock, including valid user codes and the programming code.

I'm including a link to the pdf file of the complete installation and programming instructions:

http://consumer.schlage.com/Project%20Documents/P515-859.pdf

You may also find more useful information on this page:

http://consumer.schlage.com/Service-Support/Pages/InstructionandManuals.aspx#1

Installation and programming instructions can be found here:

http://consumer.schlage.com/Project%20Documents/P515-858.pdf

You will need Adobe Reader installed on your computer, as this is a PDF file.

How can I program my electronic keypad lock when the instructions with the programming code have been lost?The back plate of the keypad side of the lock on the exterior of the door has a sticker which includes the serial number, six digit programming code and two pre-programmed four digit user codes. The lock must be disassembled to a point the exterior of the lock can be pulled away from the door and the information on the sticker made note of.

This link will give you instructions for various models of Schlage locks:
http://consumer.schlage.com/Service-Support/Pages/InstructionandManuals.aspx

Good luck!

How can I program my electronic keypad lock when the instructions with the programming code have been lost?The back plate of the keypad side of the lock on the exterior of the door has a sticker which includes the serial number, six digit programming code and two pre-programmed four digit user codes. The lock must be disassembled to a point the exterior of the lock can be pulled away from the door and the information on the sticker made note of.

This link will give you instructions for various models of Schlage locks:
http://consumer.schlage.com/Service-Support/Pages/InstructionandManuals.aspx
There is a video on this page, showing how to change codes.

Good luck!

How can I program my electronic keypad lock when the instructions with the programming code have been lost?The back plate of the keypad side of the lock on the exterior of the door has a sticker which includes the serial number, six digit programming code and two pre-programmed four digit user codes. The lock must be disassembled to a point the exterior of the lock can be pulled away from the door and the information on the sticker made note of.

This link will give you instructions for various models of Schlage locks:
http://consumer.schlage.com/Service-Support/Pages/InstructionandManuals.aspx
There is a video on this page, showing how to change codes.

Good luck!

How can I program my electronic keypad lock when the instructions with the programming code have been lost?The back plate of the keypad side of the lock on the exterior of the door has a sticker which includes the serial number, six digit programming code and two pre-programmed four digit user codes. The lock must be disassembled to a point the exterior of the lock can be pulled away from the door and the information on the sticker made note of.

This link will give you instructions for various models of Schlage locks:
http://consumer.schlage.com/Service-Support/Pages/InstructionandManuals.aspx
There is a video on that page!

Good luck!

look on the sticker located inside the outer panelo on the lock. you are going to need to disassemble the unit but it is in there.