I don't know about the 03 system, but the 94-95's grounded somewhere in the driver's side kickpanel. Might wanna take a look at the ground, especially if you did any poking around in there at all (installing gauges, and running lines in that general area, etc). Have you made any electrical system mods recently?
Hmm... Then I'm pretty much out of ideas. You may want to try posting in 4.6 Tech or SVT Tech, since they get a lot more visits than this forum. I'd move this thread for you, but I don't have access to the Mod Control Panel in this particular forum.