SeaRay fuel gauge issue

[sparks4540]

Hey everyone. Was hoping someone could provide me a wiring diagram of the dash on my '79 Searay Cuddy. I pulled the gauges from the dash one at a time to install dash cover. The only gauge not working properly now is the fuel gauge. There were like 5 black wires to the ground terminal on the gauge. Now, Turn the key and she pegs passed 'E'. I tried shorting the 'S' wire to the ground pin and the gauge does not move. I have about half tank of gas and 95 ohms on the pink sender wire which varies if you rock the boat and you can hear the sender moving. The only voltage on the gauge anywhere is on the white 'I' wires, 12V. I also have 12V on the ground pin to ground. Pretty simple circuit and I can't really explain what happened. Even with the power and sending wires on the gauge, if I ground the black sender wire to another ground point, the gauge does nothing. What in the world happened?? Any input would be appreciated..
Thanks,
Chris

 

[Silvertip]

Re: SeaRay fuel gauge issue

You should NOT have 12 volts on the ground pin. You SHOULD have GROUND on the ground pin. Apparently all of those black wires are not grounds.

 

[Jlawsen]

Re: SeaRay fuel gauge issue

The sender wire should be pink, the light in the gauge is blue, the ground is black and 12v power is purple from the ignition switch.

The symptom you're describing is usually from no - (ground). The cluster of black wires are probabaly going to other instruments and the main - (black) wire that is actually connected to battery - is not connected to the - terminal on the gauge.

 

[sparks4540]

Re: SeaRay fuel gauge issue

I'm an electrician and it's making me nuts..lol. Such an easy setup. I have the pink from the sender to 'S', 12V switched to 'I' (white wires on my boat), and if I have no ground hooked up, the gauge does nothing and I have nothing from the ground pin to a good ground. If I hookup the ground wire that was there I get 12V on the Gnd pin. The ground I am using is the original one that was on there and is daisy chained to the other gauge grounds. If I measure from the ground wire to another ground point, there is nothing on it...I don't get it...Good continuity from the wires on the sending unit to the dash. The big black main 12V is soldered to my main switch that controls all my accessories. It's nowhere near my gauges. 3 days and still at it..I'm wondering my gauge just happened to crap out.

 

[sparks4540]

Re: SeaRay fuel gauge issue

I did find this from a posting here a couple years ago. "Some senders read to ground and some put voltage to gauge, it's important the gauge and sender match or the gauge will read backward." There are 2 black wires that were hooked up to the fuel gauge that if I put a meter on them and read to ground show about 8V? Any chance these can go back on that gauge somewhere?

 

[Jlawsen]

Re: SeaRay fuel gauge issue

sparks, you need to remember that you're working with DC not AC. This is a battery circuit and there is no ground, just positive and negative. You should read 12v to ground from the I post to negative when the key is on. The sender is just a variable resistor that is in series with the circuit. When the sender moves it changes resistance and the amount of voltage going through the circuit changes. In reality, the needle on your fuel gauge is just like a voltmeter, it's reading the voltage level being allowed to pass by the resistance of the sender in it's current position (fuel level). Not sure if that clears things up or muddy's the water, I hope it helps.

 

[sparks4540]

Re: SeaRay fuel gauge issue

Thanks. Yep, I work with DC all the time as well. I have the 12V between the 'I' post and a remote ground connection. With the simply the ignition 12V and pink sender hooked up to the gauge, I get nothing.

 

[Jlawsen]

Re: SeaRay fuel gauge issue

The sender is just like a valve that is regulating the flow of current.

Do me a favor, disconnect all the black wires from the gauge. Now, connect only the black wire from the sender to the - terminal on the gauge. Put the pink on the S terminal and the Ignition 12v on the I terminal. If you have the correct black wire from the sender your gauge should work. If it doesn't make sure that the center hole of the gauge mounting strap is not touching the - gauge terminal. If you removed all your gauges you may have used the wrong mounting strap on this gauge thinking that they were all the same.

 

[Silvertip]

Re: SeaRay fuel gauge issue

And you won't get anything unless the gauge has a ground on it -- it's a voltmeter with a resistor (sending unit) across it. Here is a diagram of the fuel gauge system. It ain't rocket science. But you do need to establish a solid ground at the helm which is where the black wire in the ENGINE harness is involved. There will also be a ground buss for the BOAT circuit which is the two #8 or 10 wires coming directly from the battery to the fuse panel. Here is a diagaram for the instruments as well.

 

[sparks4540]

Re: SeaRay fuel gauge issue

The gauge external covering is black plastic and the strap on it matches. I have tried what you suggested already and no luck. Once over, I removed the gauges one by one. Diagram is right, but my 12V wires from the switch are all white in color. Here is what I have...with the white 12V hooked to 'I', pink to 'S' and the black from sender to 'G', gauge does nothing at all. No Light either, but I have 12V measured to ground at the 'G' pin and 'S' pin. If I add a ground wire to the 'G' pin, gauge goes straight to below 'E' and I have .03V measured at all 3 pins on the gauge, but the light works...

 

[sparks4540]

Re: SeaRay fuel gauge issue

Update..I disassembled the gauge and found a tiny green wire from the coil to the ground post(I think it was)disconnected. There were 2 to that post inside. I resoldered it and connected it back up. Nothing now. I have good continuity from the sending unit to the gauge. I have 12v on the 'I' and nothing on the 'S' or 'G'..the light works, but no gauge movement at all. Gonna take another look inside later. I was going to replace all the gauges with new at some point. Maybe I'm at that point right now..lol.

 

[Silvertip]

Re: SeaRay fuel gauge issue

The gauge external covering is black plastic and the strap on it matches. I have tried what you suggested already and no luck. Once over, I removed the gauges one by one. Diagram is right, but my 12V wires from the switch are all white in color. Here is what I have...with the white 12V hooked to 'I', pink to 'S' and the black from sender to 'G', gauge does nothing at all. No Light either, but I have 12V measured to ground at the 'G' pin and 'S' pin. If I add a ground wire to the 'G' pin, gauge goes straight to below 'E' and I have .03V measured at all 3 pins on the gauge, but the light works...

You need to pay more attention to the sender wiring. You said you have a black wire from the sender to the "G" terminal. WHY?? The ONLY wire you have from the sender is the PINK wire. There is no ground FROM the sender. The metal flange on the fuel tank sender should have a ground wire going to the NEG terminal of the battery or to a ground buss at the stern - not all the way up front to the "G" terminal on the gauge. Electrically thats the same as running a wire from the flange but that still leaves you without a ground for the gauge. Stop experimenting and start diagnosing.

1) Locate the ground wire in the ENGINE HARNESS. That is the wire and the ONLY wire that connects to the "G" terminal on the gauge.
2) The PINK wire is the sender wire and is the ONLY wire on the "S" terminal. It does not ever measure 12 volts to ground or anywhere else for that matter.
3) The WHITE wire is the only wire on the "I" terminal.
4) You mention not having ANYTHING on the "S" or "G" terminals. What do you expect to read on the "G" terminal. And measured from the "G" terminal to what?? Ground is ground. You can't measure voltage on ground. You can measure 12 volts relative to ground or sender voltage to ground but you cannot reference ground to anything.
5) Go to Radio Shack and buy a 100 ohm resistor. Disconnect the pink wire at the gauge ("S" terminal). Connect the resistor between the "S" and "G" terminals. Now turn the key on. The fuel gauge should read about 1/2 full. If it doesn't the gauge is toast or you still have the +12 volts and ground wiring miswired. If the gauge now reads half full, you have a sender, sender wire, or a sender ground wire issue.

 

[sparks4540]

Re: SeaRay fuel gauge issue

JLawsen up above made mention to connect the black wire from the sender to the '-' pin. Is that not the 'G' pin??? Here is his quote "Do me a favor, disconnect all the black wires from the gauge. Now, connect only the black wire from the sender to the - terminal on the gauge"..I don't have a '-' pin on the gauge, but I do have the 'G' pin for ground. The tank on this boat has never been touched. There is a pink sender wire. There are also 2 wires screwed to the top of the sender. A black one and a green one on the same screw. The green wire appears to be connected to the underside of the gas filler cap. The black wire runs to the gauge. What is the difference if the ground buss wire is connected to the 'G' pin AND the black wire from the sender is connected to the same spot on the gauge?? Ground is ground. Correct? I believe the wiring to be correct and the gauge to be bad. I have some resistors here and will do what you suggested.

 

[Silvertip]

Re: SeaRay fuel gauge issue

There is no difference between running a wire from the metal shell of the sender to the "G" terminal on the gauge and connecting the "G" terminal to ground and the metal shell to the battery. But the "G" terminal of the gauge still needs a ground wire hooked to -- well -- ground which is the negative terminal of the battery. If the gauge is not grounded it isn't going to work. You say you work with DC all the time. Did it not occur to you that the "-" symbol and "G" are the same thing. Grounding the sender "S" terminal does not accomplish anything unless you have a solid ground. Grounding the shell of the sender to the "G" terminal must means one end or the other must still find its way back to the negative terminal of the battery. Running that ground wire all the way from the sender to the gauge is a waste of wire since there is already a ground wire in the engine harness. Yes it works -- but a waste of wire nevertheless. My final bit of advice is to forget your present attack and do the following.

1) Remove the gauge.
2) Go to the back of the boat.
3) Make three jumper wires (red and black and any other color).
4) Connect the red wire to the "+" terminal and the black to the "G" (or "-" terminal)
5) Connect the third jumper to the "S" terminal.
6) Connect the other end of the RED wire to the POS terminal on the battery
7) Connect the other end of the BLACK wire to the NEG terminal on the battery
8) connect the other end of the (any other color) to the sender (remove the pink wire).
9) Connect one more jumper (any color) between the metal shell of the sender and the NEG terminal of the battery. This is the "electrical" connection I keep mentioning). You need one end or the other of this circuit back to NEG on the battery. That can be via the engine harness ground or via a jumper from the sender to the negative terminal on the battery, or to the NEG buss at the helm. But the negative buss at the helm will pass back to the battery via the BOAT harness so it too must be intact.
10) If you've done this correctly, the gauge should register whatever amount of fuel is in the tank.

Finally: You've already said the sender reads about 100 ohms with the pink wire disconnected so you know the sender is ok.
If the above steps fail to make the gauge work then only three things are possible. a) you didn't follow the instructions, b) the jumpers you made are not fashioned correctly, or c) the gauge is bad.

 

[sparks4540]

Re: SeaRay fuel gauge issue

Thanks again. My point was that I do in fact realize that '-' and 'G' are the same and this pin IS grounded to the main ground at the helm and also has the black wire from the top of the sending unit going to it. Thought I was being clear that MY gauge does NOT have a '-' pin, but just a 'G'(ground) pin. That is it. Two wires only to the 'G', or ground pin. It is a GOOD ground. Pink to 'S' and 12V to 'I'. Been doing electrical work for 20 years. I get it. Just simply wanted a little direction if the gauge was possibly bad. Sender seems fine based on the ohm readings. Already hooked the gauge directly to a car battery with a resistor between S and G. No dice. Will be ordering a new gauge set next week. Thanks.