At the sending unit, disconnect the wire that goes to the gas gauge. Now when you turn on the ignition, the gauge should go past full.
Now touch the wire to a “known good ground”. The gauge should go to empty. Don’t assume a ground is good. If you have to, take a jumper cable from the battery ground to make sure. All of these test are dependent on a good ground otherwise we will be chasing our tails.
If both of those test passed, the gauge and wire going to the gauge are good and its on the sending unit side. Now turn off the ignition.
Now reconnect the wire to the sending unit. Take a test lead and connect it to that ”known good ground” and connect the other the the ground (or body) on the sending unit. With the ignition on does the gauge show relative gas level?
If not, remove the sending unit. First check to see if the float is fill of gas. If it is replace either the float or the sending unit.
If not, with a multimeter, set it on ohm’s and connect the leads to the wire going tho the sending unit and the other to the body of the unit. Now swing the float and the meter should show 0 to 30 ohm’s. A few ohms one direction or the other is not a problem, but it should be even across the entire movement of the float and not erratic.
Report back with your findings.
Last edited by Phak1; 01/06/2021 5:26 PM.
