Here's how the gas gauge system works:
  • You have 6 volts going to the positive terminal of the gauge.
  • The negative terminal is wired to the float in the gas tank
  • The arm of the float has a needle that rubs across some windings (called a potentiometer)
  • When the float is high, there is some resistance to ground
  • When the float is low, there is very little (if any) resistance to ground

So, you can put 6 volts on the + side of the gauge and then ground the negative side. Then remove the ground. In one position, the gauge should read full, in the other it should read empty.

Paul Schmehl CI 6
geek@stovebolt.com
Stovebolt Staff: Geek