Fuel gauge not doing its thing

[azievinger]

Hello all,
I have an new challenge to solve. My fuel gauge is not working as it should.
The tank is for sure more than half full, but the fuel gauge moves an little when ignition is turned to start but doesn't continue to show the correct amount of fuel in the tank. I made and video of how much it move to give you an clue. http://vid1381.photobucket.com/albums/ah225/Alvin_Zievinger/fuel-gauge_zpsw84hdewe.mp4

I have autometer gauges, issue started after the complete wiring of the car was replaced. Like most of my current issue's. it seems like that this is the last one thought, managed to tackle all of them. Unfortunately is the person who did the rewiring for me not available to help me out.   
The dashboard is currently open to troubleshoot the issue.
Before in order to explain the picture's. There are 4 wire's going to the fuel gauge. beside's the one for the light which are black and white.
1. Pink, Has power on it when key is switched.
2. red, No clue, was pushed in together with the pink one. when removed did not had any affect on the fuel gauge acting differently.
3. black, did not removed, No clue. We thought this is ground.
4. creme(light brown). Was traced back to the fuel tank

What we have tried today to remedy the issue:
-Checked the fuses, is okay.
-Removed to connection at the tank and cleaned it and connected back, no results.
-Check the wire for the tank if it is really connected at the gauge, yes it is.
-Switched the connections at the gauge. This caused for no reaction at all at the fuel gauge.
-Check which of the connections give's power, result : pink
-Put and additional ground on the fuel tank to see if that may be the issue, no results.

What could be the issue ? In the past the gauge worked without any issue. As mentioned earlier, the tank is more than half full.
Any help is appreciated.

Alvin Z.

[Challenger_Chuck]

 I would start by bench testing the fuel sending unit sensor.  Check the ohm range of it against the particular model of Autometer gauge you have.  You might have the wrong range, just like I did when I recently replaced all of my gauges. I had to order a different range one and its now working fine.

[TelisSE440]

I would start by bench testing the fuel sending unit sensor.  Check the ohm range of it against the particular model of Autometer gauge you have.  You might have the wrong range, just like I did when I recently replaced all of my gauges. I had to order a different range one and its now working fine.

Chuck is right, check the fuel sending unit. These are the numbers that you should normally get:

L = 73.7 Ohms
M = 23.0 Ohms
H = 10.2 Ohms

M would be 1/2 a tank of gas.
If everything checks OK then put the original fuel gauge back and watch if it works, the gauges use a voltage limiter (5 volts) which may not be compatible with aftermarket ones. If you watch difference at ohm range, then most probable cause is a rotten sending unit floater, but you should take the sending unit out anyway to check it yourself. Good luck

[azievinger]

Challenger_chuck, I know made that mistake in the past as also I needed to buy another gauge. I'm sure that this gauge is an correct one for Dodge. It worked fine in the past.
TelisSe440. I understand you're figure's I just need to understand how I can measure those, an little out of my knowledge range at this point(but nothing that we cannot learn, I do have an digital multimeter, just have find out how to use it in this case).

So I decide to take you're other advice and hooked up the original gauge. See picture of wire for connection.
We connected the black wire to the creme(brown wire) coming from the fuel tank.
The red wire was connected to the pink wire which has power on it.
The needle of the fuel gauge(when key on start position) moved up to showing an half tank full. We decide to take an small drive to the gas station to put some 5 gallons into the tank to see if the needle would move further(we where hoping that), unfortunately it did no move further than half tank. Switching the wire's doesn't do anything.
As mention the only thing is we did not do is check for the Ohms readings.

Let me figure out how to do that, I'll be back

Alvin Z.