Heater controls not working

Sounds like an actuator

 

Call kenworth...they can...or ours will fax you the parts diagram that shows where it is.

Try this, pull the dash panels, shut the door, run up till your air bleeds off then shut the truck down and listen for an air leak. You would be amazed at the number of them under the dash. I do not know if yours is air operated. We have W9's and T600's and they are. Those little lines like to come loose if you ever go in there and are not careful. You can normally trace where the lines go also. Kenworth does a good job of labeling everything in the dash for you.

 

My t2000 2007 is doing the same thing;defrost only. found that hvac fuse was blown. replaced fuse and all ok for an hour or two. fuse continues to blow... Is there an electronic control unit (box) in this unit or air/electric actuators. anyone have a diagram???

thx