Fuel gauge reading empty

extremez

Petty Officer 3rd Class
Joined
Nov 1, 2007
Messages
83
This is driving me crazy now. I've pulled the sending unit and the gauge. I tested the resistance on the sending unit and it ranges from 30-200. I've tested the gauge and sending unit using 12V and it works. Reinstall it and it's again on E. I replaced the connections at the sending unit already. Not at the gauge cluster.

When the boat is running I have 12V on both Sensor and Ignition terminal of gauge.

Am I missing something? It's the only gauge not working. Is there another connection somewhere? Actually there must be because it's pink at the gauge and red at the sending unit. But I'm still getting a signal.

Could/Should I just run a new dual wire from the sending unit to the cluster bypassing whatever other hidden connection there is?
 

sam am I

Commander
Joined
Jun 26, 2013
Messages
2,169
Okay......just had too ^^^

https://forums.iboats.com/forum/boat...h-lights/page2

post #24, 3rd paragraph,

"needle on your fuel gauge and varies from around 2.3 volts (full of gas) to 5.2 volts (empty of gas). **Standard sender 33-240Ω, AMC, Stewart Warner and most all marine apps**"

You stated.....

When the boat is running I have 12V on both Sensor and Ignition terminal of gauge.

Sounds like your tank (sender) is missing its ground connection on the tank/sensor body since if we assume worst case you should see a 6 VDC max reading on the sensor wire when empty and you're seeing 12V on the signal/sensor wire.......This assumes the sender/float are working properly
 
Last edited:

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,464
Ayuh,...... Is the sendin' unit grounded,..??
 

extremez

Petty Officer 3rd Class
Joined
Nov 1, 2007
Messages
83
Ayuh,...... Is the sendin' unit grounded,..??

The black lead from the sending unit goes into the main wiring bundle that goes up towards the cluster. I believe it is grounding to the ground terminal on the gauge which is tied in to all the other grounds.

Should I try a different ground lead from the sending unit to the battery ground?
 

extremez

Petty Officer 3rd Class
Joined
Nov 1, 2007
Messages
83
So I got a little time today to look into this again. Think I tried just about every combination of testing on the boat before I pulled the sending unit and gauge again. It's a WEMA 001305 sending unit. The black lead from the SU connects to the red lead. The pink/orange lead from the SU connects to black wire. After cutting numerous zip ties to keep the factory wiring mess together the best I can tell is they run up to the cluster. I tried a test ground lead to the battery from the SU. Nothing changed. I tried another test lead from the SU to the S terminal on the gauge. Nothing.

What bothers me is the black wire that goes to the cluster from the SU is marked fuel. There's another black wire at the battery that runs in a separate bundle towards the front. That wire is bundled with a Main 20A fused red wire and ground wire. No idea what it is.

So back into the garage to hook it all up to the spare battery. This needle will not move. 12V to ignition terminal. ground lead to ground post. Another ground lead to the SU ground. Last lead from SU black wire to gauges S terminal.

Now I have 12V on ignition terminal and nothing on S terminal.
 

sam am I

Commander
Joined
Jun 26, 2013
Messages
2,169
http://www.wemausa.com/sensors/level-FuelWater.shtml

http://www.wemausa.com/instructions/...nstruction.pdf

http://www.wemausa.com/instructions/...STALLATION.pdf


*****NOTE from above***** (For sending unit......"pink to ground" and "black to gauge input")

So on the bench........wire both gauge and sender as follows:

Gauge (3 things to hook up, minimum)

1) 12V on the ig "I" terminal(battery + or red wire/pin #2)
2) Ground or "G" terminal (battery - or blue wire/pin #1)
3) Black wire from sender on gauges ("S" terminal or black wire/pin #3, goes to hookup #2 below)

Sender (2 things to hook up, minimum)

1) Pink wire to ground (battery -)
2) Black wire to gauges' "S" terminal (hookup #3 above)
 
Last edited:

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,092
with key on check for 12v at the fuel gauge , then ground the pink wire at the gauge cluster ,needle should go full
now go to the sending unit and short the sending unit wires , gauge should go full, if not use a wire from the neg side of the battery to the tank . If gauge now goes to full your missing the tank ground to the gauge cluster. If the gauge still does not respond use the wire from the neg battery to the pink wire, gauge should go full. If not the pink wire is corroded open somplace

report back with the findings
 

extremez

Petty Officer 3rd Class
Joined
Nov 1, 2007
Messages
83
Update. Haven't had a chance to work on it til today. Went out first thing this morning and bought a new gauge. Seems like the gauge was bad. Tested the new one before I installed it and it worked fine. Installed it in the boat and it works fine also.

Now on to investigate why the bilge pump isn't working.
 
Top