There is no guarantee that you will be able to download every account you have at every financial institution.
I once had a CD at Bank of America, but at that time BofA did not provide downloads for their CD accounts. I'm guessing they still don't.
My guess is that heloc accounts would be among the least likely candidates for downloading.
Try opening the heloc account at the BofA website and looking for a "Download" button. On my BofA checking and savings accounts that "Download" button is on the row just above the list of transactions for each account. "Download" has a dropdown which offers Web Connect and QIF file downloads which Quicken can use (Excel and text formats are also offered).