How To Video to Fix HVAC Wild Vent / Blend + Mode Door / Fan Speed
Administrator
Joined: Apr 2010
Posts: 87,483
Likes: 4,223
From: Clayton MI
I have had this issue where it would not change modes at all. We noticed a sucking sound coming from the dash. Further digging found the mode selector switch is vacuum operated and the ports that are on the back were cracked. We were able to find an old used one that worked just fine. Currently tho, many years later, it seems to have a mind of its own. In cruise control pulling a hill most of the time you will hear and feel the mode switch as if it lost the suction then return when you have crested the hill. And some days it won't change modes at all.
Registered User
Joined: May 2014
Posts: 13
Likes: 0
no the actuator does not move when hooked to the truck and I try to switch it from hot to cold but if I remove the actuator and probe power to each of the tabs of the connector on the actuator it works. the plastic rod that connects to the actuator is not striped
Amateur
Joined: Aug 2012
Posts: 25
Likes: 0
My issue is my vacuum line from the check valve (off of the engine) that goes through the firewall is missing. I have pulled my climate control box and all of the vacuum lines are attached on the manifold. Is there another manifold that splits the line between the engine and the controller manifold? I've pulled my dash off about 3/4 of the way and I cannot find a broken line or anywhere where this line should connect to. Or do I just need to run a new line and connect directly to the main controller?
