Wierd, I thought I replied to this yesterday.
Anyhow, Most automotive A/C systems are very similar. I just picked up an '03 Explorer this week, so I'm kind of new here. I'm an admin on Focaljet which is a Focus forum, and I'm the webmaster for FocusHacks.com which just has some how-to type of stuff for the Focus.
I just recently wrote this article on A/C service for the Focus:
http://www.focushacks.com/index.php?modid=85
If you ignore all the focus specific stuff (like locations of service ports, sensors and whatnot) most of it should hold true for our trucks as well. If I were you, I'd do the following:
1) Check the A/C Compressor wiring connector and the A/C Pressure switch connector. Look for damage and make sure they're plugged in firmly. Also check all the fuses. Double check them if you have to.
2) Pick up an A/C pressure gauge (maybe even a cheap A/C Refill kit)
3) Test the A/C pressure at the low-pressure service port with the truck turned off. The pressure should be approximately the same as the outdoor ambient temperatre. If it's 80 Degrees Fahrenheit outside it should be somewhere in the 80PSI range. If it's higher (like 110-120 PSI) don't worry too much.
4) If the pressure is very low (or non existant), Turn the truck on, turn the A/C to MAX, temp all the way cold, and blower fan all the way to 4, then start adding refrigerant. Check the pressure frequently, and don't exceed 90 PSI or so though. Eventually the A/C compressor should kick on. If it does not, then stop filling, and shut off the truck. Listen for hissing refrigerant leaks, or visually inspect the lines and compressor for leaks. They can be hard to troubleshoot.
BTW here's some pics I took to help you find the Low pressure side service port and A/C Pressure switch. They're both under the hood on the passenger side on my '03. I'd bet there's a similar layout on yours despite the 2 generation gap in body styles.
See the Advanced A/C troubleshooting information on that page I linked to. Hopefully it helps.
Linear Mode
