everything acting erratically

Hi, I have a 2004 Windstar that is nor behaving well. It seems to run ok for the time i have had it. Mileage not showing, error code for cam shaft sensor (It has been replaced), passenger window works intermittently, no display on stereo, Heat blows on drivers side while the AC blows on passenger side, Electric doors work sometimes. Any suggestions? Like i say, it drives ok but won't pass emissions and too many erratic problems to sell it. My independent mechanic thinks its the computer and said take it to ford. Cant afford for them to waste hours shooting down individual problems if they are all related.

My model is much earlier ('96) and it is a base model, so it doesn't have features such as remote keyless entry, so my advise is mostly from intuition.

If all your symptoms started at about the same time, there's a good chance that there is one common cause, but if each issue came at different points during a long period of time there is probably multiple issues.

If you want to DIY the repairs, you'll need some insight. A wiring manual might be helpful you can read and understand electrical systems.

You have a few things that seem to be related:
-No Odometer display
-No Stereo display
These are both controlled from the instrument lighting dimmer knob, so a problem with the knob will affect all instrument panel lighting. This should include other lights on the panel. Another cause could be an ambient light sensor. The ambient light sensor will automatically dim or brighten the displays to counter the effects of daytime vs. nighttime driving.

Windows that work intermittent could be related to an electronic control module sometimes called the GEM (separate from the powertrain control computer, PCM). The window power flows through the module rather than the control switch to allow for features such as single click window control and active windows for a short time after the key is removed. In my case the control module had a flaw.

Door locks are also control by a keyless entry system, which might be able to interfere with the use the regular lock controls.

I wouldn't be at all surprised to learn that the heat blend doors are also controlled by this module.

I know that later models had more than one control module in the vehicle. These are located in the passenger compartment. In my '96 there is only one module which can be found under the dash behind the center console. I believe later models have two modules.

This link may help:
http://www.justanswer.com/ford/0qn3a-body-control-module-ford-windstar.html

I would start by reading voltages on fuse tops ... and compare these readings to the battery voltage.