Reagan urges unions to back his policies

President Reagan, insisting there is ''good reason to believe'' economic improvement is on the way, urged organized labor to back his policies. Speaking to leaders of the AFL-CIO Building and Construction unions, Mr. Reagan sought to keep open lines of communication to labor by praising the union movement and accusing reporters of ignoring ''thousands of good agreements'' reached every year with management.

The leaders, however, accused President Reagan, Congress, and the Federal Reserve Board of throwing the housing industry into depression. They threatened to use their lobbying power to defeat congressmen who are not sympathetic to their views in elections next November.