fuel gauge malfunction
Here's an old reply to someone else who was in your situation:
The resistance values are based on fuel level. What does the gauge read?
If you were to disconnect the sender lead at the tank and ground it, with the ignition switch in the on position, the gauge should read empty. If it is already reading empty, then the sending unit wire may be pinched to ground somewhere along the way (most likely at the tank somewhere). If it is not reading empty now and it does when you connect the sender lead to ground, then the sending unit in the tank is at fault. If the gauge is stuck on full or beyond, even with the sender lead grounded, then there is either a open circuit between the sender and the gauge, or the gauge is bad.
If the gauge is stuck on empty even when the tank is full, but rises to full when the sender lead is disconnected with the ignition switch on, then the fuel tank sending unit is bad. If it remains on empty even after you disconnect it, then there is a short in the line that needs to be repaired.
The fuel level sender lead should be purple at both the back of the gauge cluster and at the fuel tank.
If you were to disconnect the sender lead at the tank and ground it, with the ignition switch in the on position, the gauge should read empty. If it is already reading empty, then the sending unit wire may be pinched to ground somewhere along the way (most likely at the tank somewhere). If it is not reading empty now and it does when you connect the sender lead to ground, then the sending unit in the tank is at fault. If the gauge is stuck on full or beyond, even with the sender lead grounded, then there is either a open circuit between the sender and the gauge, or the gauge is bad.
If the gauge is stuck on empty even when the tank is full, but rises to full when the sender lead is disconnected with the ignition switch on, then the fuel tank sending unit is bad. If it remains on empty even after you disconnect it, then there is a short in the line that needs to be repaired.
The fuel level sender lead should be purple at both the back of the gauge cluster and at the fuel tank.
BF Veteran
Joined: Aug 2009
Posts: 3,424
From: munster indiana
yeah i second the wire idea. if a ground wire breaks ive always seen the fuel gauge go way past full. bought a k5 before that for some reason someone cut the wire going to the fuel gauge and thats what happened it just stuck where it was at
Starting Member
Joined: Jan 2011
Posts: 207
I was just looking at my fuel gauge sending unit a couple of days ago and it's part of the pump assembly. The unit is spot welded to the assembly and it looks like to replace that part you have to swap out the whole assembly. It's a little late to check the ohms on the sending unit to see if there is a open on the windings but that's what I would do if the pump assembly was out of the tank.
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