1999 Mountaineer

when heat reaches set temperature, immediately get blast of cold air, not modulated constant heated air. Have to keep raising temperature, until it finally is at 90.....then get nothing but hot air.....How can I fix this?

when heat reaches set temperature, immediately get blast of cold air, not modulated constant heated air. Have to keep raising temperature, until it finally is at 90.....then get nothing but hot air.....How can I fix this?

It is automatic climate control right? It is doing it's job but the blast of cold air does not sound right. My fan turns down as it reaches temp i believe. I never us the automatic though.