Questioni have a 2003 f150 harley edition. recently had emission work done and ever since ac will not blow out vents but blows out defroster. when i get speed up and open a window the air will come out of vents. had diagnosed at place that did work and was told it was vacuum control module in dash and that it would cost from $500 to $1300. what do you think as another option or any suggestions?
AnswerDave
First of all, NICE TRUCK. That is what I will be upgrading to in the near future.
Ok, what is happening, or not happening rather. Inside your ducting there are several blend doors and panel doors that open and close dependent on where you set your temp. and path. for the airflow. These are all operated by actuators that are controlled by vacuum. And of course the vacuum control module is the brain so to speak. That goes out and obviously the doors stay in one position.
It comes out of the vents with the windows open because of air pressure. The air coming throught the cab lowers the air pressure inside the cab just enough for the control module to push the right panels open. You close the windows, air pressure in the cab goes back to normal and the vcm isn't strong enough to keep them open.
The 500-1300 price. Considering the labor involved in taking apart the dash alone I can see it getting up there in price. I think 1300 is on the VERY high side. I would expect about 800. Depending on your skills you can save alot of that labor cost. The control mdule will typically run about 160.00 for most of the ones I have replaced. But it is always a pain in the neck getting to it.
Not sure if this was the information you were looking for, but I agree with their diagnosis.
Sorry I couldnt be of more help.
