I really thought that now I have a very basic 4 door V8 with a regular transmission, I would be problem free for a while. What was I thinking! I remember my older cars, the vents inside the car were controlled with vacuum from the engine. If you had a vacuum leak, it could cause the vent to deflect to the windshield. Does the Mercury use vacuum to control the ducts or have they upgraded to electric? I can turn on my AC and the cold air will first come out the vents but after a minute or so, it will change to the windshield. Since the air is still inside the car, I just ignored it. After a few minutes, it will go back to the vents but won't stay there. It seems to have a mind of its own! Any idea where to start with this issue? Do I start looking for a vacuum leak or am I dealing with a computer control issue!
Well those are all electronically controlled and taking a dash apart on that thing is going to cost you well over a thousand bucks if it really has to be taken apart down to the basics. So what you do is hire a guy like me with a real fancy scan tool who knows how to use it then we can do bi-directional testing to see what actually is wrong it could be a computer module could be control unit could be the actuators on the vent system. You don't guess what the computer you can command things to happen the computer shows you did the command go out and then did the actuator move without that stuff you're just guessing
