How do I know I am getting any deduction from heloc (which line of which form) that I took against primary house and have entered 1098 from lender in turbotax

[Ashby]

Did you use your HELOC to buy, build, or improve your home? HELOC interest is not deductible if used for debt consolidation, investing, etc.

[aroraanish]

yes, I used it to improve my primary home

[Ashby]

Thanks for the info! See answer below

[Ashby · Accepted solution]

You will find your HELOC mortgage interest deduction on Schedule A, Line 8A. It will be totaled with your primary mortgage. That section will be totaled on Line 10 and flow through to your total itemized deductions. See the attached image below for exact location. 

If you are not over your the increased standard deduction for 2018 ($12k single/$24k married filing jointly), a Schedule A may not get produced.