Need some help bad. Have 2006 f350 king ranch with 6.0. has automatic a/c control. The system is only blowing out the defrost vents.
So i checked the vaccuum lines coming in and there seems to be no vaccuum. My other question is before i tear in the dash too deep, where is the actuator the activates the defrost to vent door? any help anyone could give would be greatly appreciated. I have to haul 2 hot rods to louisville this week. Gonna be hot.

 

I had this issue when I would put it in Max AC occasionally. It turned out to be the vacuum line that attached to the heater core shut off valve had popped off. I reconnected it and haven't had a problem since. You might want to check that out. I think there are some other simple things to check too, but I don't remember them right now. I'm sure someone else will be by soon to help ya out.

 

thanks for the input. i did notice the heater line valve is open. but i dont seem to have vaccuum anywhere, cant find any vaccuum lines that supply vaccuum. even at the canister on the passenger fender well doesnt have vaccuum. i tested the automatic ac control and its sending signal where it needs to. it just wont come of the defrost doors. it blows cold air out the defrost. and its 100 degrees here in alabama today.

 

There is an electric vacuum pump on the passenger side fender in the engine compartment. If you follow the line from the reservoir towards the fender you should run into it.

With the key on, remove the vacuum line from the pump and it should run. If it doesn't, check to make sure it's getting power. If it is, then the pump probably needs replaced.