Hey guys, i am trying to diagnose an issue with my 95 jimmy blow weak from the vents.

Hot heat, core is new, replaced almost all the vacuum lines behind the dash when doing the core, all vacuum switches tested good.

It will change through all the settings without any trouble..but on heat only...flow is weak.
When i switch it to cold, flow increases almost 100%. On cold you can feel flow behind the front seats...on hot...only a few inches from the vent.

I did notice that i always seem to have something blowing on the floor..but all the doors seems to be functioning properly..

I do know that the air is pushed over the evaporator all the time and just either diverted over the heat core or not based on the heat setting at the dash...SO...with that being said, i do not think the evap core is blocked..and the core is new, no leaks around the box that houses it.

Any thoughts...I also do notice that on the throttle, it will default to defrost...so that may be vacuum...but is just boggles me that cold works and blows hard...and heat blows so weak.

Thanks!

ugh, i apologize about the stupid title...i meant to add low flow from vents on heat...sorry.