errill Lynch & Co., which has pioneered the brokerage industry's thrust at traditional banking customers, announced last week it would pilot-test a new financial product designed to allow homeowners to tap the equity they have in their homes.

Roger Birk, chairman of Merrill Lynch, said the so-called Equity Access Accounts would be test-marketed in Southern California in March, and if successful it will be offered in other states.

The equity access account would give the homeowner a line of credit, similar to lines of credit granted by bank credit cards or special overdraft checking accounts. The maximum amount of credit the customer could obtain would be equal to 70 percent of the equity in a house minus the remaining balance on the first mortgage.

If, for example, a house is worth $100,000 and the homeowner still has $50,000 left to pay on the first mortgage, the customer could establish a credit line of $20,000--$70,000 minus the $50,000 first mortgage.

The customer would pay a floating interest rate that is 2.5 percentage points higher than the prime lending rate (today that would be about 18.25 percent) and could choose to pay off the balance of the loan as fast or as slow as desired. The customer could get at the money either by writing a check or using a special Visa card.