I have a problem that just started about a month ago. My A/C has always worked well, no leaks in the system, compressor is also good. When I first start the truck, the A/C blows cold. As soon as I hit the accelerator I hear a clunk in the vents then it blows immediately HOT. I was driving today on about a 3 hr trip and the A/c blows hot until I stop at a light then I switch on the Air and it works good. As soon as I hit the accelerator same thing, clunk the immediate HOT. Does anyone have and ideas about this? I think I may have a vacuum issue but I don't know alot about A/C systems.

 

Your blend door is busted and is flopping around in the plenum.

Extremely common. Many previous posts about it.

 

Thanks I wasn't sure but, I will look around to see how to fix it. Thanks.


Well I pulled the floor vent out and the acuator. When I pulled the acuator out, out fell three plastic pieces. I fould the problem now I need to fix. Not sure if I am up to pulling dash out or not.

 

the problem im having on my 1998 fl150 4x4 there is no actuator where they say it is, nothing below the dash is like what i see in pictures or videos, i have the 4.6 manual,

 

Here's how to do it on a 98 F150. Several parts.

 

thanks i downloaded all the vids , appreciate the help

 

My 1997 started blowing hot all the time a few weeks ago. I am gonna go behind glove box to fix mine cause there aint no way I am taking the dash apart. Gonna replace plastic door with metal door as well.

 

I wish mine was that easy, my dash has to come out, i have cut the hole and taken the door out but i can access my activator motor, thats why the dash has to come out, if i could bend the metal piece at the top up out of the way to get the door in i could and i may have to cut one side of the circle piece that hold the top of the door to bend it, i might could get it in but it back in there a piece and im not sure that im going to even fix it my son suggested putting 2 cutoff valves under the hood on the heater hoses and just turn them off in summer, one thing i do know is im not pulling the dash, and damn ford for making this mess

 

Why do you think it's the blend door? Are the high and low pressures correct? Is the compressor clutch engaging?

 

i cut the hole behind the dash and took out the door that was broken at the bottom, the activator is working but i have no access to it under the dash,