You will most likely find the wiring schematic for your Chevrolet in your vehicle's owner's guide. If it is not there, you should probably contact a professional.
The gauge, wiring or sending unit is bad.
the purple wire is the gauge and white and black are ground!
get a chiltons repair manual at the library for your car.
Schematic can be found at www.savageparts.com
I looked at my Chilton repair manual and the engine wiring schematic for a 1994 Ford Explorer shows ( fuse # 17 - 15 amp - for fuel gauge )
Here you go:http://smokeriders.com/Technical/wiring_diagrams/wiring_diagrams.html
need to know where to tie in to the fuel gage have a black and white omming out of fank
It is important to have diagrams on hand of a cars parts. A free wiring diagram of this car can be found in the cars maintenance manual, or at an auto shop as a print off.
Full diagnostics at: http://www.4x4wire.com/jeep/tech/electrical/gauges/
The float is stuck down at the bottom of the tank or you could have a wiring problem.
I would start by checking the fuse for your gas gauge According to my Haynes repair manual 1991 through 1994 Explorers, the engine wiring schematic shows a 15 amp fuse in location # 17 for the fuel gauge.
It is a Stevens 940B. I have the schematic. sales@countrygunsmith.net