Sterling preamp wiring no output

Currently trying to wire up a SB14 bass with a preamp from a US Sterling. I am a tech at a guitar store and we are stumped. We get slight hiss when we turn the volume knob and a few noises if we poke at a few things. Already Emailed EBMM and SBMM customer support earlier this week to no avail. Trying to get this customer hooked back up and playing again.