Fuel gauges no working 1989 ford f-150

The fuel gauge is controlled by the sending unit which is on the fuel pump. The fuel pump happens to be in the tank.


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needs change the sensor in the fuel tank

drop the fuel tank thats where most sending units are located

You just have a ground problem between the frame and tank ground. It has to be connected to a clean tab on the tank at the fuel sending unit. Check and clean them, both tanks. It gets confused and don't know what to do without a complete circuit.

Eewww. That's not good. And you're not going to like what I say. I think you bent the fuel gauge sender unit, or misaligned something when you put it back in tank. Try unplugging the connector and plugging it back in. See if that helps the gauge to register right. Here's a quick check to see if your dash gauge is working right: Unplug connector again at tank and use a jumper wire to ground the dash gauge sender wire. With key turned to on and the fuel gauge wire grounded, the gauge should jump up to half or full. If it does, there's a problem with your sender unit in the tank.

The tank switch on the dash is common to go bad. The RED is hot for the front tank, and the BROWN/WHITE is hot for the rear tank

this problem is only caused by one thing that is the fuel gauge sending unit inside the fuel tank, replace it.

you have two tanks and inbetween them there is a transfeer switch I believe your problem is there.

based on my 20 years in a Ford dealer your problem is the front pump.

Normally I'd say the float/sending unit in the gas tank is the culprit, however the fact that your service engine light is involved requires further investigation, You need to hook up an obd2 reader to the interface mounted under your dashboard and see what it has to say, there might be a simple error code preventing your gauge from functioning. Many auto parts stores will do this for you for free...