@hindmanm
That's strange that you wouldn't have a security code with a LUV voucher as I've never seen a LUV voucher without a security code. I would recommend reaching out to Southwest in a DM on Twitter/Facebook or you can reach out to customer relations by calling 855-234-4654 Monday-Friday.
I would also double check to make sure it's a LUV voucher as some people mistake a travel fund for a voucher and some mistake an Epass for a LUV voucher.
the security code should be right under the voucher number.
hope this helps!
Blake
