1974 Chevy Blazer, Fuel gauge/Fuel level sensor/wiring issue

[Detroit Iron]

I have been cleaning up the basket case wiring through out this Blazer. My question is; Does the fuel tank sensor to gauge have continuous power? I have the brown wire from the dash gauge and follow it through to behind the fuse box and cannot find an active wire of fuse. I have ran a jumper wire from the fuel tank sensor directly to the brown wire and gauge worked as well as directly to the gauge. The gauge works but when the ignition switch is turned off the gauge remains on. I cannot remember if it has continuous power of not.