Heat Problem

[97 eddie bauer]

I recently did a tune-up on my explorer, and ever since then I have been getting heat blowing out of the defrost vents, when the heat is not even on. I think it might be a vacuum line or something. Someone please help out.

 

[BrooklynBay]

Welcome to this forum! Plastic vacuum lines are known to crack at the base where they connect. Check all of your rubber, and plastic lines for any cracks. Maybe one of them came off?