The connection to the sensor is on the back of the fuel tank. It is the cable you have to disconnect when removing the tank. I thought mine didn't work, so I replaced the sensor. That didn't seem to work either. It turns out it was working fine, it just doesn't come on as soon as I expect. Last time I removed the tank I dumped out almost all of the fuel before re-assembly and tested it again. It worked fine.
But it would be easy to damage the wire coming out of the back of the tank. It gets pinched pretty tight. Also, the indicator light can fall out of the holder, so you won't see it.
