Heater problem
2001 GMC Jimmy 6 cyl Four Wheel Drive Automatic 83,500 miles

I can't get the heat to work on my vehicle. The fan blows great, a/c works great, only cool air comes out when heater is on, will not heat up at all. No smells, just clean cool air.

My jimmy did that 2 years ago. Its a 2000 and one shop told me I needed to replace the Heater core. I took it in to a shop that works on the radiator and told me it was clogged up with radiator fluid. They did a huge flush. They said the made a special tool. They seen so many jimmy's with this problem and they fixed it. A huge flush cost me 300 and worth it. A new heater core is almost 1000. Try a deep flush. Maybe a radiator expert shop.