Giving it one more try

[5150]

Giving my fuel gauge one more chance before I put my glock up to the plastic and pull the trigger, hoping that I don't hit my master cylinder.

Pulled out the plug and for some reason I have power to the pink wire(20P) now, but who cares I do have power. The only confusing thing is that the black ground wire(18B) with the U-Clip on it is not grounded it's just lying in the floorboard.

But as usual it can't be the only thing wrong, I always find somethingelse wrong. One of the wires at the bottom of the plug is not plugged into anything. Both wires are close in color, but I have a heater so I figure it's the other one. This might be why I have no dash lights if the cluster lamp wire is just lying around.

Where does it go?

[jhow66]

You do not need the DARK BLUE wire as it went to the oil pressure LIGHT on old set up--so you will have 1 wire that goes no where. If ground wire is not hooked up you will have no dash lights. Hook it to the flange on lower dash.
P.S. Watch radiator when you shoot it --makes a mess.

[5150]

Well it's the grey wire that goes nowhere. The thing that confuses me is the the ground isn't even hooked up and the pink wire has power.

I'm starting to think my post on this subject is pissing people off since hardly anybody wants to reply to it. I know I'm a moron some of you are just now learning this revelation.

[byrd]

The grounding is used for lighting and signals for the gauges.Fix the ground issue and hopefully that will fix the fuel gauge problem, now as for the gray cluster feed wire, yes that would be why your dash lights and light on your heater controls isn't working. I believe that wire should connect on the load side of the headlight switch, you should check to see witch wire gets hot off the headlight switch when you turn on your parkings lights and that would be what you would need to turn on the cluster and heater controls lights. Hopefully this may elp, and I don't thin you are pissing anybody off, I think that them like me are about all outof suggestions to help you.. Randy

[jhow66]

Did you follow the step by step guide by GMCPaul? Grey wire should hook in #8 slot on cluster with gauges. If you have the dark blue wire hooked up take it loose.

[5150]

Okay GREAT NEWS!!!!! Just got the dash lights to work. I think the plug in the back is not right. If I pull it out a little bit they come on. The ground wire looks like it was splice at one time so I just cut it there and grounded it underneath the dash. I don't think that was the problem though.

BAD NEWS!!!!! Still do not have a working fuel gauge. The grey wire is apparently the wire to the light bulb at the heater control. Problem is that the bulb holder is gone altogether. I'll try to find one in a junkyard I guess. It's just the empty hole behind the heater control.

[jhow66]

Try this for guage:
1--unplug this wire (Tan) for fuse panel.
2--take a jumper and hook to where it plugged in.
3--turn on switch
4--ground the other end of jumper and watch guage --if it moves guage ok
5--trace wire you unplugged back to tank and see if it is hooked to tank.
6--if ok plug the wire back into fuse panel.
7--disconnect the tan wire from tank (switch still on) and touch to ground-if gauge moves gauge ok--sending unit bad.
8--if in #4 gauge does not move check to see if you have gauge wire plugged into right slot. If ok check out printed circuit. If ok change resistor on back of guage--get buy it here-cheaper then a whole guage.
www.fix-a-gauge.com

[pjmoreland]

I don't remember all the different things you have already checked on the fuel gauge, so I'll start from the beginning just to see if I can add anything that might be useful.

The pink wire provides power from the fuse panel to one terminal on the fuel gage. The tan wire provides a connection between the other terminal on the fuel gauge to the sender in the tank. The sender connects the tan wire to ground, through a variable resistor.

It seems to me that your problem is going to be one of three things:
1) Bad wiring
2) Bad sender
3) Bad gauge

The first thing I would check would be to make sure the wiring is good.

Power Wire (pink) -- You said that the pink wire has 12 volts on it. I'm guessing that maybe you measured the 12 volts at the connector that plugs into the back of the gauge panel. I would take that one step further and make sure you have 12 volts on one of the two terminals that are on the back of the fuel gauge. You can follow the trace on the printed circuit board from the pink wire to the gauge to see which terminal is connected to the pink wire.

Signal Wire (tan) -- Disconnect the tan wire from the sender (behind your seat). Use a test light or an Ohm meter to make sure the end of the tan wire that you just disconnected from the sender has a good connection to the terminal on the fuel gauge that is connected to the tan wire.


If your wiring all checks out ok, then I would test your fuel gauge next. With the tan wire still disconnected from the sender, your fuel gauge should be pointing all the way one way (I don't remember which way). Then touch the end of the tan wire to a known good ground, and the gauge should move all the way the other way. If the gauge doesn't move, then I'm guessing there is something wrong with the gauge. If it does move, then I'm guessing there is something wrong with your sender.


You could test your sender by removing the tan wire from the sender, and use an Ohm meter to measure the resistance between the terminal on the sender and ground when the tank is empty. Then go fill your tank up and measure the resistance again. I have no idea what the two resistance readings should be, but at least they should be different from each other. Somebody else will probably have an idea of what the two resistance readings should be.

Good luck getting it figured out. It's a pain to have to keep track of how many miles you have driven since your last stop at the gas station.

[5150]

When I pull the wire off the fuel sender the gauge doesn't move. So I you may be right-as much as don't want to replace the gauge that might be it.