I was just wondering how this thing is setup. I assume there are 3 wires, one hot with the key on, one ground and one that sends a particular voltage back to the gauge. My s10 has been reading empty ever since I changed the clutch, so i am assuming I messed somthing up when i pulled the trans. I was just trying to think how i should go about tracking down exactly where the problem is. If i can know how the damnthing is supposed to work, i can go at it with a multimeter. Sorry, this isnt exactly 3rd gen related, but the people on the s10 board are a bunch of yahoos that want to put turbos on 2.2L trucks that have cavalier engines.

 

Ok, this is how the gauge works. On the gauge there are three wires, Ignition power, sender, and ground. Only one wire goes to the tank the sender wire. Now with that said the sender is basicly a resistor. Chevys sending units are normally 0 to 90 ohms resistance. The sender is grounded and when the flote moves it changes the resistance to ground thus moving the needle in the gauge cluster. I would start by checking my ground connections ie. make sure that the tank is grounded. What ever you do DO NOT PUT POWER TO THE SENDING UNIT. If the tank is grounded then take an ohm meter and measure the resistance from the sender wire (normally a tan wire, but could be diffrent) and the chassis of the truck. If it shows resistance then that will tell you if the sender is working. Other than that your gauge could just be junk.