Alright. Thanks for all the help and patience. Now the fun starts.

 

All right folks, let's get this problem solved. Six pages for a fuel gauge is pretty long. Here is the deal:

1) Stop focusing on that yellow pigtail behind the dash. It has nothing to do with the fuel gauge, as kingofcows correctly pointed out early on. The thick BLACK/GREEN wire that feeds the pigtail is a 12-volt accessory tap. The ICVR resistor wire happens to source off that same signal elsewhere in the harness, but that pigtail is upstream of the entire fuel gauge circuit.

2) If you have 12 volts at the actual sending unit connection, then as I have been saying all along, someone has modified the wiring and bypassed the fuel gauge circuit completely. OR, the ICVR and resistor wire are shorted out. Either case would explain why the wire smoked when you grounded out the connector. You STILL need to assess the damage this caused. You shouldn't be applying power to anything until you figure out what smoked and where.

In fact, it sounds like you inadvertently measured the resistance between hot-in-ACC power and the sending unit feed, and got almost a short circuit. That is BAD.

To solve this problem, you're going to need to trace out the entire path that I listed on the previous page by doing the following:

a) Verify that the power to the ICVR (BLACK with GREEN stripe bundled with a dummy wire at the cluster connector) has 12 volts unloaded. This is a VOLTAGE measurement.

b) Verify the resistor wire is intact by measuring the resistance between this same connector and one of the connectors in the yellow pigtail - not because that has anything to do with the fuel gauge, but because it's an exposed accessory tap that you have access to. You should see 8 to 9 ohms. This is a RESISTANCE measurement.

c) Verify the output of the ICVR is 5 volts. This is a VOLTAGE measurement.

You will find the issue during one of those three steps. Let me know if you need assistance with the different settings of the meter, or how to take a proper meaurement.

 

Well, I will need further assistance for sure, but not till tomorrow. When I tested the IVCR the meter jumped all around. It wasn't steady, it went from 9 thru 1 on the volt meter. Whats this mean?

 

Well, after all the questions and all the answers, I have figured this out. When I took the entire dash out to paint it I didn't pay real close attention to all the connections because there aren't too many really. Well, when I put it all back together after painting the dash, I plugged two connectors together that looked as though they were a match made in heaven and they were, however not for my truck. After cutting all the tape from the harness I was able to follow the wires from the gauge to the proper connector. I then turned the key and what do you know, the fuel gauge works properly. I felt like such a "rookie" for lack of a better term.

Thanks to all who had the patience to help me out and stick with my on this thread. One thing is for sure, if anybody else has a fuel gauge problem this thread will definitely explain how to figure it out.

 

Glad you got it worked out, but make sure you hunt down what smoked. It's not completely clear to me what solved this problem; based on what you described it almost sounds like someone had swapped the pins in your instrument cluster or bypassed wiring.

 

I'm having the same problem and I will try all of these ideas and see if they will work I'm new to the site