None of the dash gages work no fuel, no rpm no speedometer

More than likely a broken wire, corroded connector or a chafed wire.

What make , model an year vehicle ? If a GM vehicle 2003 to 2006 stepper motors in the instrument cluster are bad .
How to repair GM Instrument Cluster Speedometer Gauge Stepper

I didn't see an s15 in that model year, in my database?
If the speedometer works but the tach doesn't, I think something is wrong with instrument cluster?
GM has had a problem with fuel gage sending units. The sending units are not hard wired to instrument cluster, they send signal to pcm, the pcm sends serial data to instrument cluster, telling the cluster the gage settings.
It may be possible to use different size resistors in place of the fuel level sending unit, to see if fuel gage reacts properly to different resistors, if the gage reacts properly, then I think the problem is the fuel gage sending unit.

first check all your fuses and relays, if they all check good you may need to have the instrument panel repaired

maybe pixels gone bad check that.

try this website reliable-store.com
they help you with all this stuff, ask the girl at the bottom for help
they give manuals under like $10 and it's very useful as well
must try

I'd wager that the fuse that controls the gauges is shot, or one of the internal connectors got unplugged (Fuse sounds more likely). Radio, Lights, and Turn Lamps are usually on seperate circuits.

Have you checked the fuses? Look in the owner's manual for the locations... you might have just blown one.

Have the computer checked

you need to check your fuses

sounds like a popped fuse to the cluster

if that don't work dis-connect the battery for a sec

good luck