electrical/fuel sender question

[goose slayer]

Just purchased a 1990 sylvan King troller. the fuel gauge works when I flip the Nav switch on and illumanates the gauge, but does not work with just the key. I checked the gauge and it is wired correctly in the dash. At the sender the pink wire is on the center stud and the black and green wires are in the tab. I followed the black and green wires only to find that the other ends were connected together but to nothing. Where should these be connected? I assume they are ground wires, but I don't see where the screw came out of.

 

[Bondo]

Where should these be connected?

Ayuh,.... Welcome Aboard,.... The green wire bonds the hull to the fuel system, the black wire goes to battery ground,.....

 

[Silvertip]

The gauge is NOT wired correctly if it doesn't work with key in the RUN position. It definitely should not work the way you describe. Turning on the NAV switch should light the NAV lights and illuminate the gauges but it should not provide a fuel level reading on the gauge. The "I" terminal on the gauge gets +12 volts from the ignition switch. The"S" terminal should have the pink wire from the sender attached to it. The ground terminal on the gauge goes to ground. +12 volts and ground for the gauge can also go to the +12 volts and ground connections on any other gauge.

 

[goose slayer]

Thanks I'll check the gauge

 

[goose slayer]

Gauge seams ok. Pink on S black on G and purple on I and L

 

[Silvertip]

Think about this! It cannot be wired correctly if it doesn't work with the key in the RUN position. Although the appropriately colored wires may be in the right spots on the gauge, the other ends of those wires must not be or the gauge would work with the key in the RUN position as it should. How about the other gauges? Do they work only with key in the RUN position?

 

[UncleWillie]

... and Purple on I and L

The Purple wire should have 12v on it when the Key is ON.
Toggling the NAV Lights should have No effect on the Purple Wire.

Trace the Purple to see where it goes astray.

 

[goose slayer]

Ok the purple wire comes from the remote throttle that dead ends and is connected to the gray wire that comes from the harness. Then connected to the bottom prong on my nav/ anchor switch. There is another purple wire that is in a harness that goes to another harness that goes to the MPH gauge then to the fuel gauge. As far as gauges I only have fuel and miles per hour but I have three toggle switches. I did try to unplug the gray wire from the nav switch but that did not work. I also unplugged the gray wire and ran a jumper from the purple on the mile per hour gauge to the prong on the nav switch and that did not work

 

[Silvertip]

See what I mean when even though colors and connections on one end may be correct they may not be on the other? This wiring is hosed up. I will be as detailed as I can and will make this last effort (step by step) to help. You need to follow this 100% and stop jumping around looking for a quick fix. The gray wire in that harness is the tachometer send wire from the engine is not where the purple wire should be connected.

1) Find the wire in that control box harness that has +12 volts on it when the key is in the RUN position. It comes from the "A" terminal on the ignition switch. If you cannot do this, stop and get someone to help you that has a bit of electrical knowledge.
2) Disconnect the purple wire from the gray tach wire. Nothing should be connected to the gray wire so insulate it if there are bare wires remaining.
3) At the speedometer, disconnect and remove the wires going to the "L", "I" and "ground" terminals. Remove them! Yes, I said remove them. I will explain what this is all about later. You want this right do you not?
4) Connect the purple wire you disconnected in step #2 to the wire from the control box that has 12 volts on it. The one you located in step #1.
5) Make sure that purple wire goes to the "I" (+12 V) terminal on the gas gauge.
6) Make a short jumper wire and connect one end to the "I" terminal on the gas gauge, and other end to the "I" terminal on the speedometer.
7) Make another short jumper wire and connect one end to the ground terminal on the gas gauge and the other end to the ground terminal on the speedometer.
8) Make another short jumper wire and connect one end to the "L" terminal on the gas gauge and the other end to the "L" terminal on the speedometer.
9) The pink wire from the fuel sender in the tank was correct and should remain on the "S" terminal of the gauge.
10) The speedometer has no sender signal as the water pressure tube serves this purpose.

The speedometer and gas gauge are now daisy chained so the fuel gauge feeds power, light and ground to the speedometer.

Now to the NAV lights as well as any other accessories.

11) If you want the gas and speedometer internal lights on whenever the key is on, then jumper the "L" (light) terminal on the gas gauge to the "I" terminal on the gas gauge. If you want the internal lights to be on ONLY when moving at night, connect the "L" terminal to the NAV position (not the center terminal) on the NAV switch.
12) Make sure the ground terminal on the gas gauge is connected to the BLACK wire at the control box or to a known good ground behind the console.

At this point you should understand that the main engine harness is not designed to power accessories such as navigation lights, radios, spotlights and other non-engine related accessories. A separate #10 gauge pair of wires are typically run from the battery to a fuse panel at the helm. Accessories, including your navigation lights are wired to that panel through a switch. If your boat doesn't have such a configuration then I strongly suggest you add one. But to make the NAV lights work correctly the power to the switch goes to the CENTER terminal of the switch (assuming it is a rocker or toggle switch). The bow and stern lights get connected to the terminals at either end of the switch. The light ground wires go to ground wherever you find it.