Need help with gas gauge - The 1947 - Present Chevrolet & GMC Truck Message Board Network

9teen69 · 05-18-2003, 10:17 PM

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 · 05-18-2003, 10:45 PM

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

9teen69 · 05-18-2003, 11:25 PM

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

Longhorn Man · 05-18-2003, 11:33 PM

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 · 05-18-2003, 11:34 PM

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

Longhorn Man · 05-18-2003, 11:51 PM

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 · 05-18-2003, 11:56 PM

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 · 05-19-2003, 12:00 AM

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 · 05-19-2003, 12:04 AM

Thanks for the help!

GMC_Aaron · 05-19-2003, 12:54 AM

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 · 05-19-2003, 06:49 PM

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 · 05-19-2003, 07:14 PM

mines stuck past full...any ideas?

Green72GMC · 05-19-2003, 07:34 PM

Quote:

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 · 05-19-2003, 09:04 PM

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

9teen69 · 05-19-2003, 09:25 PM

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 · 05-19-2003, 09:29 PM

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 · 05-19-2003, 10:01 PM

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 · 05-19-2003, 10:52 PM

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 · 05-19-2003, 11:03 PM

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

Longhorn Man · 05-19-2003, 11:32 PM

I produce gas...just ask my wife.

Seke69 · 05-20-2003, 07:12 AM

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 · 05-20-2003, 10:59 AM

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 · 05-20-2003, 01:20 PM

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 · 05-20-2003, 11:24 PM

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 · 05-25-2003, 03:51 PM

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?!#

05-18-2003, 11:25 PM	#3
9teen69 Registered User Join Date: Sep 2002 Location: Austin, Texas Posts: 1,048	It's on below empty. I haven't seen it move at all __________________ 72 Cheyenne SWB C10 (daily driver) (Super fake cause I just love the glovebox emblem) 70 Camaro RS (frame-off in pieces) 70 Camaro RS (daily driver backup) 69 Custom LWB C10 (son now drives)

05-18-2003, 11:34 PM	#5
9teen69 Registered User Join Date: Sep 2002 Location: Austin, Texas Posts: 1,048	I checked that wire- its good. That's the wire I used to plug into my working aftermarket gauge. __________________ 72 Cheyenne SWB C10 (daily driver) (Super fake cause I just love the glovebox emblem) 70 Camaro RS (frame-off in pieces) 70 Camaro RS (daily driver backup) 69 Custom LWB C10 (son now drives)

05-18-2003, 11:56 PM	#7
9teen69 Registered User Join Date: Sep 2002 Location: Austin, Texas Posts: 1,048	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. __________________ 72 Cheyenne SWB C10 (daily driver) (Super fake cause I just love the glovebox emblem) 70 Camaro RS (frame-off in pieces) 70 Camaro RS (daily driver backup) 69 Custom LWB C10 (son now drives)

05-19-2003, 12:04 AM	#9
9teen69 Registered User Join Date: Sep 2002 Location: Austin, Texas Posts: 1,048	Thanks for the help! __________________ 72 Cheyenne SWB C10 (daily driver) (Super fake cause I just love the glovebox emblem) 70 Camaro RS (frame-off in pieces) 70 Camaro RS (daily driver backup) 69 Custom LWB C10 (son now drives)

05-19-2003, 12:54 AM	#10
GMC_Aaron Registered User Join Date: Jul 2002 Location: Ventura, Ca. Posts: 87	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. __________________ Aaron Ventura, Ca. 1972 GMC Super Custom SB350/TH400

05-18-2003, 10:17 PM	#1
9teen69 Registered User Join Date: Sep 2002 Location: Austin, Texas Posts: 1,048	Need help with gas gauge 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? __________________ 72 Cheyenne SWB C10 (daily driver) (Super fake cause I just love the glovebox emblem) 70 Camaro RS (frame-off in pieces) 70 Camaro RS (daily driver backup) 69 Custom LWB C10 (son now drives)

05-18-2003, 10:45 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	What is it doing? Is it stuck on past full, below empty, or is it stuck some where inbetween E and F?

05-18-2003, 11:33 PM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	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.

05-18-2003, 11:51 PM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	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?

05-19-2003, 12:00 AM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	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)

05-19-2003, 06:49 PM	#11
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	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.

05-19-2003, 07:14 PM	#12
Chevyguy111786 Registered User Join Date: Apr 2003 Location: Garland, Texas Posts: 1,127	mines stuck past full...any ideas?

05-19-2003, 09:04 PM	#14
dinnut Registered User Join Date: Apr 2003 Location: missouri city, tx Posts: 4,486	mine is way past full too. anybody else with us? __________________ 70 longbed 496/th400/Ford 9"

05-19-2003, 09:25 PM	#15
9teen69 Registered User Join Date: Sep 2002 Location: Austin, Texas Posts: 1,048	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? __________________ 72 Cheyenne SWB C10 (daily driver) (Super fake cause I just love the glovebox emblem) 70 Camaro RS (frame-off in pieces) 70 Camaro RS (daily driver backup) 69 Custom LWB C10 (son now drives) Last edited by 9teen69; 05-19-2003 at 09:28 PM.

05-19-2003, 09:29 PM	#16
Chevyguy111786 Registered User Join Date: Apr 2003 Location: Garland, Texas Posts: 1,127	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.



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05-19-2003, 10:01 PM	#17
72chevyLWB Got 20's???? Join Date: Oct 2001 Location: Aberdeen SD Posts: 1,451	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 __________________ 99 Silverado Ex-Cab 2wd, Bagged&WhippleCharged 02 Sierra Ex-Cab 4wd 2500 HD The 72 went down the road.

05-19-2003, 10:52 PM	#18
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	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.

05-19-2003, 11:03 PM	#19
Chevyguy111786 Registered User Join Date: Apr 2003 Location: Garland, Texas Posts: 1,127	i'll check that as soon as possible...so much for my gas producing truck

05-19-2003, 11:32 PM	#20
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	I produce gas...just ask my wife.

05-20-2003, 07:12 AM	#21
Seke69 Space Cadet Join Date: Mar 2003 Location: Twin Cities Posts: 132	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!

05-20-2003, 10:59 AM	#22
9teen69 Registered User Join Date: Sep 2002 Location: Austin, Texas Posts: 1,048	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. __________________ 72 Cheyenne SWB C10 (daily driver) (Super fake cause I just love the glovebox emblem) 70 Camaro RS (frame-off in pieces) 70 Camaro RS (daily driver backup) 69 Custom LWB C10 (son now drives)

05-20-2003, 01:20 PM	#23
guypm Registered User Join Date: Feb 2002 Location: orange, tx usa Posts: 167	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 __________________ guypm 1971 SWB Fleetside/350 performer rpm heads &intake/ holley 750dp/1.5roller rockers/MSD6a/700r4 1650stall/one piece driveshaft/3.73 open/dynomax ceramic coated headers/3chamber flowmasters/

05-20-2003, 11:24 PM	#24
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	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.

05-25-2003, 03:51 PM	#25
9teen69 Registered User Join Date: Sep 2002 Location: Austin, Texas Posts: 1,048	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?!# __________________ 72 Cheyenne SWB C10 (daily driver) (Super fake cause I just love the glovebox emblem) 70 Camaro RS (frame-off in pieces) 70 Camaro RS (daily driver backup) 69 Custom LWB C10 (son now drives)

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