intermittent nav lights and fuel gauge problem?
 

1999 Donzi 26ZX new to me with new motor and having a few gremlins..... nav lights work about 1/2 the time as well as the fuel gauge. I was able to find the ground wires on the fuel sensor and on the tank itself and there was quite a bit of corrosion I sanded off.... I also removed the ground block in the engine compartment and sanded off all the connectors to a shiny brass color! There was also quite a bit of corrosion there as well.
I changed my gauges around a bit and removed the non-working speedo and installed a spare Furuno GPS chartplotter I had and it all works fine. I did notice another power block and ground block behind the gauge panel and there was some corrosion there. I am thinking this is a grounding issue and will clean the front grounding block and see what happens....... anybody else have a similar problem? This boat sat for 2 years with no engine and I wonder if the main engine plug might be a factor here? All grounding points on the engine block are clean fwiw..... TBF

Well, I guess everybody likes electrical gremlins about as much as I do!

Ground or maybe the switch for the lights getting funky? Possibly swap it for another like the blower real quick and keep workin it?

Did sanding the ground down on the fuel tank fix the fuel gauge?

I think it did help a little but the answer is no.... problem is still there....... I sanded down the ground on the fuel sender itself, the extra ground wire going to a tab on the outside of the tank and also the whole grounding block in the engine bay........ I will clean up the remaining ground block behind the instrument panel today. All the gauges use a common ground wire and this includes the switch for the nav lights and also the fuel gauge...... I did pull the nav light and clean up all the connections there and it bench tests perfectly....... I also had an extra switch plugged in the nav light spot and it did not make a difference so I think the existing switch is good....... I hate electrical problems..... I would almost rather change a starter than deal with this!

If you think the switch is ok, it might be time to turn on the light and start moving/wiggleing wires around to try and find one that might be broken or have loose connections.

Might need a second person, not sure, but that's what I would try after getting the grounds clean.

OK thanks... I did not get a chance to look at it today but will tomorrow....

If corrosion was as bad as you said. There may still be corrosion inside the connector itself causing a lack of electricity. Be careful sanding connectors they may have a protective coating on them and sanding removes that and corrosion comes right back and even worse sometimes. Maybe replace the connector all together than coat them in CPC. Keep a slight loop in the wire away from the connection area and it will help moisture run down the wire and drip off instead of onto the connection.

I had one engine that wouldn't start, looked everywhere, swapped modules, swapped ign. Switches with the one that did start and even at one point took to a marine mech. their suggestion was a new harness (YEA right). Brought it back home and traced each wire best I could.. Took me 3 days... Found a connector behind the dash allllll the way in the corner. Un plugged it,, looked ok, maybe just a tad surface corrosion on one pin. Cleaned it, little elec grease plugged it back in and whola, fired right up...been good ever since... Bet you have a bad plug connection somewhere, being your having lights and gage issue.. Have fun,, it sucks but proved to be a valuable lesson for me and I got to know my boat real well,,, may have cussed her out a few times too.. But we love each other again, ;)

Great info! I will check for a plug or two and see what I got.......

Connectors have corrosion bad.... these are plastic and not shrink wrap protected..... I tried separating one and 2 wires just broke off with just lightly pulling..... looks like I found the problem! thanks fellas!