Morning, I have replaced the blend door actuator in April when I got this truck; and then blend door yesterday. My ac worked before doing this but no heat. So I knew that the blend door was broken. Now my problem is with the new blend door actuator, when i turn on the truck to see if the actuator is working and is turning, it does not turn. I can hear the actuator working but not moving. Could this be a control **** issue? I'm stumped..

 

it could be a number of things, but when I had to replace my heater core a few years back, I seem to recall having to fix a vacuum line to the controller after all the stress I put the dash through to get the heater core out. If you are sure the actuator and circuit board controlling it are good, check for vacuum leaks either right behind the ***** or even the line off the engine. I have had so many vacuum leaks in the past few years as all the rubber on the truck seems to be degrading now. Try changing your vent settings on the AC controller when the engine is running and listen for that faint hissing sound as the system adjusts. (it should hiss but I recall thinking to myself my blend door is not changing but im also not hearing that hiss I usually hear), there might be a vac leak somewhere preventing the system from moving those doors. If the leak is bad enough it could even make your engine run rough. Not too long ago I got the code for minor leak to the fuel evap system and my engine was running so rough I thought I had blown a spark plug or cracked cylinder. However it was just a small 3 or 4 inch section of 1/2 or 3/4 inch pipe that had a hole where it naturally bent over. It was impossible to see unless I pinched the pipe. The factory pipe rubber was gummy and felt like black silly putty. it was the cheapest fix for the worst looking problem I think I ever solved.