Why would the instrament cluster fail on a 2003 Ford Focus?
It's bad quality PCB! Ford should recall the instrument cluster for 2003-4 models. Googled and found a UK forum with thousands complaining about Ford Focus clusters. The problem seemed to be the same for all owners, and it's corroded PCB (printed circuit board). Did what that forum suggested. It worked!!!
How to fix it:
1. Buy a electronic contact cleaner ($5) from pepboy
2. Disconnect battery
3. Take out the instrument cluster. Need to disconnect two cables. Took a couple of minutes to disconnect the second, the black thing is the key. Needs loosen 7 bolts first, then loosen additional 5 to expose the PCB.
4. Spray PCB the hell of it.
5. Bring in home and dry overnight
6. Re-install cluster
7. Re-connect batery cable.
8. Done! Good luck! Less than 30 min hand work in total.