i recently installed a new trolling motor in my boat.  I am running two 12 volts for the trolling motor, one cranking battery for the outboard and one 12v deep cycle for the electronics/everthing else.  My setup before was one 12v deepcycle for the trolling motor and one 12v cranking battery for the outboard and electronics/everything else.  After making the change everything works great except for the gas guage.  I won't mark how much gas I have.  Before the switch it was working great.  Can anyone give me some advice on what it might be or what I might have done wrong?  Maybe some information on how to trouble shoot the problem.  Anything would help.

Thanks in Advance,

with anything electronics related, always double check the connections, especially the ground...

My instruments were hooked on to the cranking battery.  Now they are hooked up to a 12v deep cycle.  The battery is used just for the instruments.  Every other instrument works.  Tilt, pressure, battery, speed, and rpm guages all work except the gas.

Have you checked the voltage at the back of the gauge to make sure there is power? Any fuses that can be double checked?

Next I was thinking maybe the bobber in the tank may be stuck or rusted (had that happen on an old Ford).

I am just trying to think of the various connections but thats really all there is to a gas gauge.

Check 12V power to back of gauge and any fuses it may use; if thats ok check the fuel bobber in the fuel tank; if thats ok, then during the switch it may have caught a short and killed the gauge.

I probably shouldn't mention it but a neighbor down the street thought his gauge was broken too but someone had just siphoned all the gas out of the tank so it was on E.