Nope, gauge is a separate circuit. It can fail completely, and the only thing that stops working is the gauge.

 

Okay so I've been tracing wires all day and it looks like a dark blue goes the whole way back. I have a Haynes manual and it's showing me from the cluster the dark blue controls it. I didn't find any cuts from the pump to the firewall. Where it goes from that plug right behind the drivers fender I do not know. And it says that a black with white stripe wire is the ground. But I can't find where it's grounded. I lose it right there too. To check the ground can I just piggyback a wire to the frame? And do I just cut the black and white and splice it into another temp ground? Or do I cut the dark blue (power) and run a ground from it? I want to fully test this before I condem the sending unit or gauge. Cause the gauge works. It flickers and bounces around depending on if I'm braking or in the throttle. If I'm heavy in the throttle the gauge will go way up. Then when I'm off the throttle or braking it will go back down to E

 

If you can unplug the connector, short those two pins together with a little piece of wire. Turn the ignition on, does the gauge peg on full?

 

The black/white and the darkblue? I think those are the right colors. Can u verify before I try it? I had the plug out of the sending unit. Try to jump it there at the sending unit? It's a 5pin plug but only has 4 wires. I was nervous to try before I know which ones are which. I didn't know if the unused pin in the ground itself?

 

According to FSM (model year 1995), ground location G111 is next to a power steering pump on a V8 engine. From there it goes to splice, continuing to connector C125 (which is located at the left dash panel), next is C128 which is located at the front of the second body mount under the drivers feet), last connector is C328 which is the tank module connector at the tank (two wires for the gauge sender, two for the fuel pump). Dark blue goes through connectors C328 and C128, and from there it goes to instrument cluster connector B and cavity 11.

You could open the connector C128 or C328, and with multimeter test the sender. Select ohms from the meter, locate DB and BK/WT wires and corresponding pins, connect probes to pins and check the reading. Full tank is 9 ohms, half tank 32.5 and empty is 97 ohms (this also answered to my earlier question ).

 

This is the wiring diagram I was going by. Is this why I can't find the ground cause I was looking for G119 . Is this diagram wrong? I'll test the sender today. After I buy a new multi meter. It got ran over acouple weeks ago

 

I tested the sending unit. I pulled the connector at the tank and touched the prongs with my gauge and nothing happened. It didn't read anything. Am I doing something wrong. I put my meter on ohms. And touched the red to the darkblue wire prong and the black to the black and white wire prong on the top of the pump. Does the ignition need to be on? Or am I testing the wrong thing. It should read something right?

 

Of course you need a 12V power source to test the gauge...

 

I thought when testing ohms. It was the resistance of current through a circuit. Cause when I stuck the probes to the frame it was giving me a reading.?

 

My bad, I was doing too many things at one time. I just read you were reading the sending unit. When the thread started I thought you were going to test the gauge - where you would need power. No you don't need power.

You should see about 10 ohms at full to about 120 at empty. So the output would depend on how much fuel is in the tank.

I usually pull them and bench test one so I can move the float through the range...