Hi, The Sending UnitThe
sending unit is located in the
fuel tank of the
car. It consists of a
float, usually made of foam, connected to a thin,
metal rod. The end of the rod is mounted to a variable resistor. A
resistor is an electrical device that resists the flow of electricity. The more resistance there is, the less current will flow. In a fuel tank, the variable resistor consists of a strip of resistive material connected on one side to the ground. A
wiper connected to the gauge slides along this strip of material, conducting the current from the gauge to the resistor. If the wiper is close to the grounded side of the strip, there is less resistive material in the path of the current, so the resistance is small. If the wiper is at the other end of the strip, there is more resistive material in the current's path, so the resistance is large.First of all, the guage needs a 12 volt electrical supply to operate. The entire system extends from the fuse block inside the front passenger compartment, through a resister (which lowers the voltage), on to the float assembly inside the gas tank then on back to the fuel guage itself,
First , test the fuse responsible for the fuel guage. Note: this fuse is usualy responsible for the fuel guage only or several items.
If the fuse checks OK, then a check must be made to troubleshoot the entire length of the system or until the problem is located.
If the fuel tank sending unit is faulty, the fuel guage can read any position, including full or empty. The sending unit can be tested by first checking to see if the unit can be removed from the fuel ttank by either partially or fully lowering the tank.
Prior to removing the sending unit, check to ensure there is voltage at the wires leading into the fuel tank.
With voltage confirmed, remove the unit and check for continuity at each end of the float arms travel .with a multimeter If the unit does not check good, replace the unit. Note: Sometimes after a long time in service the strip of resistive material can wear through and plainly be seen.
If the unit checks good, there could be a bad ground somewhere along the line.
If all else checks good, then the fault most likely is a bad fuel guage. The guage also can be tested by applying varying degrees of voltage (0-12VDC ONLY) to the teminals at the rear of the guage.
If the guage is bad, it must be replaced.
I hope this information has been of assisstance to you,
Randy Atchley
First of all, the guage needs a 12 volt electrical supply to operate. The entire system extends from the fuse block inside the front passenger compartment, through a resister (which lowers the voltage), on to the float assembly inside the gas tank then on back to the fuel guage itself,
First , check test the fuse responsible for the fuel guage. Note: this fuse is usualy responsible for the fuel guage only or several items.
If the fuse checks OK, then a check must be made to troubleshoot the entire length of the system or until the problem is located.
If the fuel tank float sending unit is faulty, the fuel guage can read any position, including full or empty.
If the wiring is all good
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