* Market awaits U.S. payrolls report on Friday * ADP private sector employment weaker than forecast * ISM non-manufacturing employment component slips By Luciana Lopez NEW YORK, April 3 (Reuters) - Prices for U.S. Treasuries gained on Wednesday after tepid jobs and service sector data dampened hopes for strong numbers from Friday's key labor market report, driving investors to safe havens. Benchmark yields touched three-month lows after payroll processor ADP reported that U.S. private-sector employers added 158,000 jobs in March, fewer than expected. Separately, the Institute for Supply Management reported that growth in the U.S. services sector slowed in March to the lowest level in seven months. "We are revising our forecast for March nonfarm payrolls down 40,000 to 160,000," said Joseph LaVorgna, managing director and chief U.S. economist at Deutsche Bank Securities. Such views were "bullish for bonds, which are testing the low end of their recent yield range," said Jake Lowery, Treasury trader at ING in Atlanta. The benchmark 10-year Treasury note, down 3/32 of a point before the data was released, was up 15/32 in the late afternoon in New York, the yield easing to 1.811 percent. "We see a 1.73 percent to 2.07 percent range for 10-year yields; slightly longer term, it looks like 2.15 percent to 1.73 percent," said William O'Donnell, head of U.S. Treasury strategy at RBS Securities in Stamford, Connecticut. "Near-term resistance is around 1.83 percent." Analysts in a Reuters poll forecast a rise in nonfarm payrolls of 200,000 for March. Now that expectations have eased in the wake of the ADP data, a payrolls jump of 200,000 or more could prompt a drop in bond prices. But the magnitude of a retreat might be relatively modest since bond investors had leaned toward being short, based on the strength of recent U.S. economic data, Lowery said. "The magnitude of a setback could be less than what it would have been had investors been positioned quite long." The medium- and long-term trend for the labor market will also be important, said Steve Van Order, fixed income strategist with Calvert Investments in Bethesda, Maryland. If the unemployment rate edges down toward 7.4 percent before the Federal Reserve's year-end expectations - "then the probability of QE being tapered goes up in the market," he said. The Federal Reserve is now buying $85 billion of mortgage-backed securities and U.S. government debt per month. Investors are trying to figure out when the Fed might pull back on that aggressive easing. Policymakers have said they want to see the unemployment rate, currently at 7.7 percent, closer to 6.5 percent. As part of its unconventional monetary easing, the Fed bought $3.73 billion of Treasuries maturing between February 2019 and March 2020 on Wednesday.