Can the IRS keep your refund due to a trailer house repossesion 15 years ago

The IRS can offset a refund for back taxes, delinquent child support or delinquent student loans.  TurboTax never knows about offsets to your refund.  If your refund is offset by the IRS or your state, you will receive a letter about it afterward.

https://www.irs.gov/uac/tax-refund-offsets-pay-unpaid-debts

https://ttlc.intuit.com/community/refunds/help/what-is-a-refund-offset/00/26301

Reduced Refund     https://www.irs.gov/taxtopics/tc203

 NOTE: You can contact the IRS Treasury Offset Program Call Center at 1-800-304-3107 to ask if they have an offset for you on file. TurboTax would not have that information.

https://turbotax.intuit.com/tax-tips/tax-payments/who-can-garnish-an-income-tax-refund/L7cPPzDyc

Was the debt cancelled from the repossession?  That would affect your tax return, and if you owed money from that the IRS could withhold future refunds to pay off that debt.