There is at least one known major difference between FS2002 and FS2004 and that is that their GPS systems are incompatible. The Zodiac CH640 was designed for FS2002 but, if you know what you are doing, you can make it fly under FS2004.
The CH640 uses the native GPS for FS2002 (gps.gau) and three Garmin gauges designed for the FS2002. These Garmin gauges are an Audio gauge, a Transponder gauge (Xponder) and a GPS gauge. These are the GMA 340 (Audio), the GTX 330 (Xponder) and the GNS 530 (GPS). Now this is just a guess (and I mean a guess) but the Audio and Xponder gauges might still work for FS2004. I will just about guarantee that the GNS 530 and certainly the FS2002 gps.gau will not work for FS2004. The trick is to replace these gauges in the panel.cfg file of the CH640.
Let's attack the native GPS problem first. Go to the panel.cfg file for any aircraft that you currently know flys with the native FS2004 GPS gauge. Open this panel.cfg file with Notepad. Write down the name of this GPS gauge exactly as it appears for the FS2004 native GPS. There will be numbers after the gauge name but these are only location and size numbers. Ignore these numbers for now.
Next go to the panel.cfg file for the CH640 and open it with Notepad. Find "gps!gps" in the file and erase only the gps!gps part and then replace it with the exact name used for the FS2004 native GPS. Do not change the numbers after the CH640 gps gauge as we will try the same location and size numbers for the new FS2004 gauge. Now be sure to hit "Save" in order to make the changes permanent for the CH640 panel.cfg file.
Our next problem is to replace the GNS 530 gauge (designed for FS2002) with an FS2004 compatible GNS 530 gauge. I would suggest that you go on the internet and down load this file -------"fsgarmin.zip". This file contains a GNS 530. Follow the instuctions on how to install this gauge to your FS2004 "Gauges" folder". You must now go to the CH640 panel.cfg file and replace any reference to the "old" GNS 530 with references to the "new" GNS 530 much as you did for the native GPS. Good luck.
