Gauge or wiring issue? Electrical gurus, help!

[38fordpickup]

I know that Daytona gauges don't have the best reputation for quality, but the set in my '38 Ford pickup has worked fine for close to 10 years, only thing I don't like about them is the lighting in them is poor for night driving. Anyway, driving my truck some yesterday and noticed all of the gauges (oil, fuel, temperature, and voltmeter) were dead, traced it down to a blown fuse in the gauge feed circuit. Put in a new fuse, which blew the instant I turned the switch on. Wiring harness is an '80s vintage Ron Francis kit that has served well. Is this more likely to be a bad gauge that is blowing fuses or a problem in the harness? If it's a gauge, is there any particular one more likely to be the culprit?