Need help with gas gauge

[9teen69]

I've replaced my sending unit and gas gauge - still not working. The sending unit is good because I tested it with an autometer gas gauge and it works. Circuit board seems to be intact too.

What am I missing?

[Longhorn Man]

What is it doing? Is it stuck on past full, below empty, or is it stuck some where inbetween E and F?

[9teen69]

It's on below empty. I haven't seen it move at all

[Longhorn Man]

Inspect teh brown wire going from the tank to the fuse box. Look for corrosion/cuts anyplace along it.
It goes under the chrome trim at the bottom of the door. This is a real good place fore wires to get messed up with water which leads to corrosion.

[9teen69]

I checked that wire- its good. That's the wire I used to plug into my working aftermarket gauge.

[Longhorn Man]

Well if the wire is good, then there is a problem with the sending unit. That's the only thing left in the system.
Where and when did you get it?

[9teen69]

Classic Industries. It's only a few months old. My aftermarket gauge works fine though.

I have a buddy with a 67, guess I could borrow his cluster and see if it'll work. Not sure if the wiring is the same.

[Longhorn Man]

As long as they are the same set up...as in dummy light inst panel and dummy light or guage type and guage type. Don't try to swap one for the other...that'll fry the fuel guage if it is any good.
Double checking the circuit board would be a good step...but swapping it out would eliminate that. (I just re-read your original post...I thought you said that the circuit board was new)

[9teen69]

Thanks for the help!

[GMC_Aaron]

Don't rule out the gas guage. I had the same exact problem with mine. I pulled the sending unit out and decided to replace it since the screen was thrashed and thought that would do the trick. I also checked all of the wiring and that was good, so the only thing that was left was the guage. I bought a new one from LMC and threw it in expecting everything to work and it didn't. I was pissed! I knew it was the guage. I needed it bad because I was packing to leave in 2 days for a fishing trip and a 6 hour drive. This drive has very few gas stations along the way, so a functional gas gauge was a must. I called a local shop, Brothers, here in SoCal that specializes in our trucks and had them send me a new gauge next day air. I got it and it worked! Thanks Brothers! I will never buy anything from LMC again. This isn't the first time I've had a problem with LMC. Good luck.

[Longhorn Man]

I was thinking about this thread today at work and I didn't mention anything about the guage...
It is not real common, but it does happen.

[Chevyguy111786]

mines stuck past full...any ideas?

[Green72GMC]

Originally posted by Chevyguy111786
mines stuck past full...any ideas?

Mine is also, even when I got it wired up direct. way past the full, all the way in the marks on the side.

[dinnut]

mine is way past full too. anybody else with us?

[9teen69]

Man! I guess I uncovered an epidemic.

Are there any other wires that hook up directly to the gas gauge? Is the standard harness plug all there is? I ran a splice from the brown wire in the harness plug to my aftermarket gauge and it works.

So I'm getting a signal from the tank - to the fuse block - to the wiring harness - but the gauge is not responding.

Gotta be the gauge, right?

[Chevyguy111786]

I thought it was great...untill i noticed it wasn't goin down. "WOW!! I've got like 3 tanks of gas compressed into my one. I HAVE A GAS PRODUCING TRUCK!!" man if only my dreams came true.

[72chevyLWB]

My printed circuit fried on my truck. One of the bars going to the fuel guage burned up and it also took out my temp guage. I tried soldering a wire on to jump over the burned spot, but it still doesn't work. Any help??? And my needle goes way past full. Thanks

[Longhorn Man]

If the needle is way past full, then that brown wire is probably grounded out. The fact that it goes past full will prove that the guage and everything else is good. Just find the grounded portion of the brown wire and then hope the sending unit its self is good.
Again, under the chrome trim is the #1 place for the offending damage.

[Chevyguy111786]

i'll check that as soon as possible...so much for my gas producing truck

[Longhorn Man]

I produce gas...just ask my wife.

[Seke69]

9teen69, maybe your fuel gauge reads empty 'cause you're out of gas... seriously. I do stuff like that all the time.

my gauge doesn't work either, because the brown wire, that's supposed to be down by some chrome trim (which I don't have), has disappeared along with half of the floor!

[9teen69]

I'm a redneck but not that red. It is sitting way past empty. Thanks for the help. I'm going to borrow another cluster gauge from a buddies working truck. If that works I'll know the new is no good, I'll also try swapping out the circuit board.

[guypm]

Ive replaced my metal float 3 times. It seems to crack at the seam . Anybody know who might make a plastic float ? Or maybe a good metal float ?
Guy

[Longhorn Man]

You could put a cork float on it. Just make sure you finish drinking the bottle of wine before you donate the cork to your truck.

[9teen69]

My sending unit has to be good because it works with the aftermarket gauge. I used 2 different gauges from a friends truck and it still doens't work. When the aftermarket gauge isn't grounded good it doesn't work.

Is there a ground wire somewhere I'm missing?!#