1973 - 1979 F-100 & Larger F-Series TrucksDiscuss the Dentsides Ford Truck
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In my 1974 F250 4x4 (highboy) the fuel gauge is not working. I replaced the sending unit and nothing. I checked to see if there is power when the ignition is switched on and acc and there is. What else could be the problem? Any thoughts?
I was having trouble with all the gauges on my 75 when I first bought it. Spent days chasing wires and reviewing schematics... The root of my issues boiled down to the schematics not necessarily being 100% accurate.
The trouble as it turned out was with the ground. I am not the best person to explain this but basically instrument clusters work off the ground versus the power. And there are two grounds, a general and one with the resistance wire; once I determined where each was and where they went the cluster lit up lit a xmas tree.
I even went so far as to replace the entire cluster but the same issues were present; I later found out that the clusters don't often go out. Its usually the wiring going to the cluster that has the issues.
Disconect the wire that goes to the sending unit and ground it. If the gauge goes to full then the problem is either the new sending unit or the ground. If the gauge still reads empty with the wire grounded, the problem is either the gauge itself or the wiring.
Okay, I took the wire on the top of the sending unit and "grounded" it. I held it one of the bolts that holds the sending unit in place on the tank and after some sparks and smoke, the gauge never moved. The orange wire got very hot as I held it to ground it out. Do I need to remove the actual ground wire to conduct the test or leave it there? I left it in its place and like I said the main wire to the sending unit got very hot and the gauge never moved.
I had to pull my gauge cluster out of mine and clean the copper circuit board up with some fine sandpaper. take the piece off that is for the gas gauge, clean it and under it..go all around the whole circuit board, taking every bulb out and cleaning around it, along with takin off the little nuts and cleaning under them as well.
If the gauge is bad, who makes replacement gauges?
I saw a setup which replaced the entire cluster and trim all the way over to the climate control and radio with a piece of aluminum with cutouts for the accessories; the gauges were all aftermarket... Autometer I believe. If I wasnt trying to stay closer to the original look i would do this. It was really nice and clean plus durable.
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