Make sure all the little connectors are making good connection.
While the American Elite series were great basses, I understand that a more-than-normal amount of them developed preamp problems.
It’s time to take the bass to a qualified guitar tech well-versed in guitar/bass electronics. Alternately, you could just go on and get a good replacement preamp like a Nordstrand, Audere, or go for the gold, a John East J Retro preamp. The Elite pups will work well with any of those preamps and others as well.