'98 Chevy S-10 Pickup heater blowing cold air

szarafinski1: Thanks for your suggestion to my problem . concerning my truck blowing cold air with the heater turned on. To answer your question: yes my truck blows cold air at all three levels (floor, mid and defrost). You said there could be a "problem with the tempature door actuator". Where is this located, is it diffucult to replace and how much does it cost for me to replace? Are there any special tools needed to complete the job.