Where do I enter home equity line interest deduction?

It goes in the same area as a Home Mortgage 

Mortgage

To enter mortgage interest

• Click on Federal Taxes
• Click on Deductions and Credits 
• Click on I'll choose what I work on (if shown)
• Under Your Home
• On Mortgage Interest, click on the start or update button

Do I add my regular mortgage interest and heloc interest together? If I do this I will have a different amount from my 1098. My 1098 only shows interest for the first mortgage.

What you should do is first enter one of them and go through the screens and then it will say, "Add a lender" and enter the 2nd one, if the same bank just type in something like Wells Fargo-HELCO for the home equity.  This also helps next year in reminding you that there are two loans and not to overlook one of them.

Post additional comment if still have questions.  Thank you

Thank you