I recently disconnected my battery to try to get my compresssor running again to recharge the system. In doing so I must have upset the computer because the readout reads LO and the mechanical gage shows none but the tank is completely full. I can't imagine at all the tank sending unit being bad. How do I reset the computer to fix the fuel tank prob. Thanks!

typically there is a reset option of button, perhaps in the fuse box? im not familiar with your vehicle, but GM likes putting reset buttons in the fuse box.