Gas gauge doesn't work. What could it be?

[1990LXDropTop]

My gas gauge recently stopped working. It always reads on full now when the car is actually low on gas. Is there a sending unit that could cause this? If so where is it located? The tank?

 

[jaymac]

yup; mine is the same. Sending unti located in the tank. Anywhere from 80-120 bucks depending on where you get it. I just watch my miles and fill up when I know I'm closing on 1/4 tank. To me, it's not worth the cost. if I was gonna sell it, then I'd replace it...

 

[HISSIN50]

Another possibility is that the sender wire shorted to ground.

Good luck.

 

[5.0Droptop]

or the float fell off the sending unit, thats what mine did,

 

[vikingpower]

Another possibility is that the sender wire shorted to ground.

Good luck.

Thats what happened to me, I went out and bought the sending unit, $100+, and then when I dropped the tank I discovered it was just the ****t y factory wiring that had disintegrated. The original sending unit looked to be in excellent shape though. So I rebuilt the wiring and put the new sending unit in anyways. Major pain in the ass and the wallet for a quick fix that actually only needed about $2 in parts to correct the problem

 

[JB66]

I just replaced tanks on both my Mustangs. The connectors for the fuel pump and sending unit tend to disintegrate and leave the wires hanging. Probably why yours is grounded. If you look above the tank seam under the rear bumper just to the right of center, you will find the 4 pin connector for the pump and sending unit. Disconnect it and see if the gauge drops to empty. BTW... the gauge wires go toward the center of the tank, and the pump wires toward the filler pipe.

 

[87gtconv]

I changed tanks and my gauge problem went away along with my leaky tank! Got the tank on eBay for $80.