I had a failed heater core. After pulling the dash and putting in a new one, now I don't have any cool air. When I turn the **** to change the air temp, I only get 100% hot air. What did I miss or do wrong?

 

Sounds like you didn't reconnect the blend door actuator motor properly or there is an issue with the connection. The temp control **** is electronic and sends a signal to an actuator that opens and closes a door in front of the heater core.

 

Does anyone know where that connection is located? I am just hoping I don't have to pull the entire dash out again. Thank you for your reply.

 

It's behind the black plastic cover where the heat vents are on top of the floor hump. Pop off that cover and it should be on the right hand side.

If that is fine, the dash bezel pops off real easy with a butter knife or something similar to take look at the back of the control ****.

 

So, I traced the connection from the back of the switch after taking out the control box and the wire heads up into the back of the dash and disappears where I can't see it. I don't know where it goes from there. I looked for any connections on the left and right of the floor hump and didn't find anything meaningful. I double checked everything I could see and find on the driver and passenger side. Nothing appears out of place. I am going to take out the passenger airbag tomorrow to see if that helps me any... Probably not but I can't think of anything else. Does anyone have any other ideas?

 

One other thing to keep in mind is that the blend door on these trucks almost always tend to break over time from getting brittle with age and the heat. The motor could be working fine and just the connection point to the plastic blend door could have been broken messing around with the dash. Youtube blend door for F150 and you will get plenty of videos with location of the actuator and door itself.

 

So, #1 yes, the connection I thought had nothing to do with the blend door was the blend door actuator. You were correct on the location. It just seemed too far to the driver side to me based on the heater box location, I was wrong. #2, the actuator had gone bad. Probably because antifreeze made it in when the heater core leaked. I replaced that and it is working now. Thank you for your help.