Just installed a new Livorsi fuel sender, that's the type without the float arm.When I turn my switch on,the gauge only goes to 1/4 even though the tank is FULL,also the indicator lamp on my engine compartment light rocker switch glows ,even though the rocker switch is in the off position.When I turn the rocker switch on,the fuel gauge dops below empty.When I disconnect the sender lead,the indicator lamp on the rocker switch does't glow,and engine comp. light still works properly.
Any IDEAS
Thanks
Steve

sounds like some confused wiring. if it is the 3 wire unit you should make sure of an independent good ground. alot of boat manufacturers piggy back t he ground from the illuminated switches to the guages them selves or tie them in some how, hence your glowing problem.

purple = ignition
pink = sender
black = ground

use a fresh length of triplex, isolate the fuel gauge from switch wiring , should omit your problem. if not start checking for bad grounds. and poor or corroded connections.

What happens when you jump the ground wire to the sender port on the gauge? It should peg to past full, if not you might have a faulty gauge. It took me 2 days to of troubleshooting and 10 minutes speaking with Livorsi to figure out a bad gauge.

Just for the hell of it,I ran a jumper wire from the fuel tank to the engine block.The gauge went to full and the indicator light on the rocker switch went out.Guess the tank either wasn't grounded or had a bad ground.Thanks for the input Monstaaa,and Velocity Driver.....
Steve

Just FYI fuel senders run between 33 ohms (full) and 240 ohms (empty)