Ok, I noticed it a few times, but today it really irritated me. I usually don't run my A/C or heat unless my fiance is in the truck cuz he always says, "You know what is nice about this truck it has (fill in A/C or Heat here depending on the weather). Anyways, I noticed today, after him being in the truck last night that even if I have it in the OFF position it still blows hot air. Any reason? It doesn't blow like it would on full blast, but enough to make a difference and irritate me when I'm in the truck and don't want it on or to waste the gas with it on.

I appreciate any input. I'm flat out irritated by this.

 

could be your blend door is not closing all the way to isolate the heater core from your cold air. It sounds like you may have a vaccuum leak and the blend door is not funtioning properly. Check to see if the vents work under all the various blend settings.

 

I'm pretty sure a 99 has an electric motor that operates the blend door. The motor could be bad or the tab is broke. There is a fix some where on DF for the broken tab/linkage.

Edit, https://dodgeforum.com/forum/2nd-gen...-door-fix.html