Quote:
Originally Posted by hdixon
Can anyone shade a little light on gas tank sending unit. I have a LMC 20 gallon gas tank rear mounted that I installed and am a bit confuse or loss on how the sending get it's power. I've notice that there is a black wire on connected to the top ring and appears to be a ground wire. where dose the positive 12v power from? Do it come form the dash bezel and all I need to do is make sure the unit is grounded not sure any help would be great I am loss again.
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The power to the gas gauge comes from the fuse panel when the key is on and goes to the cluster plug for the dash and then to the gas gauge.
The gas sending unit does not get any power, it is a path to ground for the gauge. the arm on the sender is connected to a variable resistor to ground and it changes the connection to ground as it moves up or down with the amount of gas in the tank.
Think of it as a light bulb with power to the light bulb (gas gauge) and a ground from the bulb (sender wire) that has a lot of resistance to ground or little resistance to ground. IF the resistance is high the bulb will be dim (gauge reads full) and if the resistance is low the bulb will be bright, (gauge reads empty).
The gas gauge sending unit wire runs from the gauge back through the fuse panel down under the drivers sill plate to the gas tank sending unit. The sending unit is grounded to the tank which must be grounded to the frame to finish the circuit.
Hope this helps.