gas gauge
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Elder User
Joined: Apr 2003
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From: Cheney, Wa
gas gauge
is there anything qwuerky about the gas gauges mine is dead and i tried a new voltage regulator on the gauge cluster and it didn't change anything. i was wondering if there is a way to bypass any of the stuff or a quick fix to make it work? any tips would be helpful because i know its going to be a pain. thanks!
Laughing Gas
Joined: Jan 2004
Posts: 913
Likes: 2
From: Pensacola, FL
do you have dual tanks? i took off my dash trim one day to work on the stereo, put it back together and the guage didnt work. i was getting ready to rip it back apart and figure it out when i saw that the tank switch was moved to the middle between the two tanks....ie no reading. just a suggestion.
Elder User
Joined: May 2003
Posts: 549
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Gas gauges act funny sometimes. I have a gauge on a truck that only works when it rains. 
It's a clean truck, not rusted or rotting, it just has that quirk. I don't drive it much, so I don't bother fixing it. Best thing to do is systematically troubleshoot the parts until you find the problem. Check for power, check the sending unit, check the wiring.
It's a clean truck, not rusted or rotting, it just has that quirk. I don't drive it much, so I don't bother fixing it. Best thing to do is systematically troubleshoot the parts until you find the problem. Check for power, check the sending unit, check the wiring.
Postmaster
Joined: Apr 2000
Posts: 2,838
Likes: 6
From: SD
Seems the most common problem with the fuel guage is the wiring and connections near the tank. Bad wiring and poor connections will cause it to not work, work intermitantly or have a false reading.
There are two wires on the sending unit, one goes to the dash and one is a ground to the frame. Usually the wires are all brittle and broken. I usually replace the bad wires (solder and heatshrink all splices) being carefull to have clean connections and use dielectric grease to prevent corrosion. I've done this on several pickups, it usually takes me less than an hour of work (no need to remove the tank) and I get years of trouble free service...
Marty
There are two wires on the sending unit, one goes to the dash and one is a ground to the frame. Usually the wires are all brittle and broken. I usually replace the bad wires (solder and heatshrink all splices) being carefull to have clean connections and use dielectric grease to prevent corrosion. I've done this on several pickups, it usually takes me less than an hour of work (no need to remove the tank) and I get years of trouble free service...
Marty
Senior User
Joined: Mar 2004
Posts: 103
Likes: 0
From: Cincinnati
superswamper,
There is really nothing special about the fuel gaging system of these trucks, they use the same methods employed since the 30’s. I recently had a similar problem with the fuel gage on my 79 Custom 4X4.
The fuel gage circuit consists of the sending unit in the fuel tank, the gage in the dash, and the wiring and dash circuit board between them. marka, is correct, best method of identifying the defective component is to ground the wire coming from the fuel tank. There is an electrical connector near the tank that can be separated for tank removal. This makes an excellent place to connect a ground lead. Once grounded, the fuel gage should read fuel scale, ignition switch on. If it does, you have one of three possible problems; 1. The sending unit in the tank is defective. 2. As in my case, the fuel float rooted off, causing the gage is not to move up and down with fuel levels, or 3. The ground wire to the fuel tank is corroded or missing. Item three is especially important since this is a primary cause of intermittent problems. To verify the tank is grounded, place one lead of a multimeter, or conductivity test light to a clean unpainted spot on the frame, the other on the tank. The conductivity test light should illuminate, or the multimeter in resistance mode should read near zero.
If the gage does not go to full scale when you ground the wire coming from the tank ignition switch on, the problem is most likely the gage. To test this, remove the gage cluster. Using a multimeter in voltage mode, or a 12V test light, ground one lead to bare metal, place the other lead on the mounting studs of the gage. You should read 12V on the meter, or the test light should illuminate. If no voltage at all, there is an open circuit in the dash circuit board, or you forgot to turn the ignition switch on. If you see voltage on one side of the gage and not the other, the gage’s internal field winding is most likely defective.
Next, ground out the gage stud whose wire goes back to the tank. If the gage goes full scale, the wire between the gage and tank is defective. If nothing happens replace the gage.
Keep on truck’n
John24255
There is really nothing special about the fuel gaging system of these trucks, they use the same methods employed since the 30’s. I recently had a similar problem with the fuel gage on my 79 Custom 4X4.
The fuel gage circuit consists of the sending unit in the fuel tank, the gage in the dash, and the wiring and dash circuit board between them. marka, is correct, best method of identifying the defective component is to ground the wire coming from the fuel tank. There is an electrical connector near the tank that can be separated for tank removal. This makes an excellent place to connect a ground lead. Once grounded, the fuel gage should read fuel scale, ignition switch on. If it does, you have one of three possible problems; 1. The sending unit in the tank is defective. 2. As in my case, the fuel float rooted off, causing the gage is not to move up and down with fuel levels, or 3. The ground wire to the fuel tank is corroded or missing. Item three is especially important since this is a primary cause of intermittent problems. To verify the tank is grounded, place one lead of a multimeter, or conductivity test light to a clean unpainted spot on the frame, the other on the tank. The conductivity test light should illuminate, or the multimeter in resistance mode should read near zero.
If the gage does not go to full scale when you ground the wire coming from the tank ignition switch on, the problem is most likely the gage. To test this, remove the gage cluster. Using a multimeter in voltage mode, or a 12V test light, ground one lead to bare metal, place the other lead on the mounting studs of the gage. You should read 12V on the meter, or the test light should illuminate. If no voltage at all, there is an open circuit in the dash circuit board, or you forgot to turn the ignition switch on. If you see voltage on one side of the gage and not the other, the gage’s internal field winding is most likely defective.
Next, ground out the gage stud whose wire goes back to the tank. If the gage goes full scale, the wire between the gage and tank is defective. If nothing happens replace the gage.
Keep on truck’n
John24255
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