What's this wire?

[Lumpy Grits]

Check the voltage with the engine run'n, if you can. You should see 12+ vdc at that plug. GND your (-) probe to clean bare frame steel.
LG

 

[oldjeeplady]

Another thing I should mention in talking with Posi about this is that if you connect your sending unit, but you have a bad ground to it, you can ruin the sending unit. Obviously, yours has not been connected...so make sure you have a good ground when you do.

And yes, my voltmeter ground was connected to a good ground when I made that measurement.....

 

[007]

That's very good to know. I'll hit the spot where I plan to attach it with the Dremel so it's bare metal before I attach it.


Sent from my iPhone using Tapatalk

 

[Lumpy Grits]

OJL-That was quite a bit of voltage drop you posted. Close to 30% loss.
LG

 

[007]

So should I be looking for at or near 12 V to the sending unit?


Sent from my iPhone using Tapatalk

 

[Lumpy Grits]

The sender is grounded by a single wire that is screwed to the frame's crossmember above the tank.
This GND wire attachment, is the source of many faulty fuel level readings.
Yes on 12vdc reading with engine runing and a fully chg'd battery.
LG

 

[007]

Well it is hot on the key. I will start it up here in a bit and test voltage running. It hops around like crazy with key only but never got past 8.5 on a sitting 12.75 battery.


Sent from my iPad using Tapatalk

 

[007]

Well it IS the sending unit wire. Tested it out with a meter and its around 7-9v and when out to the tank the gauge slowly rises.

THANKS TO ALL. I truly appreciate the help and thoughts and input. I do.


Sent from my iPhone using Tapatalk

 

[Lumpy Grits]

THX for let'n us know.
LG

 

[Peanut Butter]

On models that have a hard top, there is a wire in the back that is connected to the hard top for a dome light near the rear gate. Could it be that?

 

[007]

On models that have a hard top, there is a wire in the back that is connected to the hard top for a dome light near the rear gate. Could it be that?

No, we wondered that, but it was the fuel sender wire. Tested it out and gauge works...

 

[Peanut Butter]

No, we wondered that, but it was the fuel sender wire. Tested it out and gauge works...

Must of skipped over that part sorry.

 

[Lumpy Grits]

PB-Isn't that dome light activated with the headlight switch, when you rotate the knob to the right?
LG

 

[Lumpy Grits]

No, we wondered that, but it was the fuel sender wire. Tested it out and gauge works...

Confirm please-The line is only 'hot' when the ign key is turned, correct?
LG

 

[007]

Confirm please-The line is only 'hot' when the ign key is turned, correct?

LG

Will check this evening, but if it weren't the correct wire the gauge wouldn't work would it?


Sent from my iPhone using Tapatalk

 

[Lumpy Grits]

Will check this evening, but if it weren't the correct wire the gauge wouldn't work would it?


Sent from my iPhone using Tapatalk

The fuel sender power supply lead should not be energized with the ign off.
That gauge, like all others, will work when energized.
LG

 

[007]

The fuel sender power supply lead should not be energized with the ign off.

That gauge, like all others, will work when energized.

LG

I understand that the gauge will work when ergized, but how else would it be energized if that was the only positive wire I was using?




Sent from my iPhone using Tapatalk

 

[Lumpy Grits]

If that is the correct lead-Your good. If that lead is a constant 'hot'(not controlled buy the ign switch), then you have another supply lead to find in the harness that is controlled by the ign switch. You don't want your gauges 'on' all the time, do you? Real quick battery killer.
LG

 

[Hedgehog]

Remember this, the power supplied to your fuel gauge will pulse, it won't be a constant. The power comes from the engine temp gauges power rectifier. Why pulse? It's jeeps way to stop the gauge from reacting to every road pump and pot hole. People like a nice steady fuel gauge, pulsed power was the answer.

If it's hot you have a power source to the rear. Hot all the time (a power source)? Hot with the switch on (Switched power)? Hot with the lights on (light power)? Hot when one of the turn signals are on (extra signal or hazard light power). Hot when the brakes are on (extra brake light power). Hot in reverse (extra back up light power).

I still want to know what the plastic/rubber piece is on the end of the wire. Is it a plug of some sort?

 

[Lumpy Grits]

HH-That's a weather proof 'female' connector.
LG