how do i replace the heater core and the heater control valve on 1995 GMC Vandura 2500

ithe blower works but i am getting no heat in the front of the van

Asked by for the 1995 GMC Vandura 2500
You need a diagnosis- we charge 60.00 to troubleshoot a no-heat complaint on one of those. More likely the blend door that directs the air in the dash is not functioning correctly is the cause of the problem.