Gas gauge troubleshooting

Start by unplugging the temp and fuel sender wires from the senders. Turn the ignition switch to the on position. If you get any movement in the temp or fuel gauge needles, you have more problems than the IVR or sending units. Something in the instrument cluster or wiring. If no movement in the needles, turn the ignition off again, and connect a jumper wire from the temp sender wire conductor to a good ground. turn on the ignition again and check for movement on the temp gauge. If it now moves toward hot (don't let it peg) turn the key back off and do the same test with the fuel sender wire. If the tests don't move the gauges, you have bad senders, a bad IVR, cooked gauges, circuit board problems, or opens in the wiring. If one gauge works and the other doesn't, most likely a bad sender, but, there again, it could be a circuit board problem, cooked gauge, or open wire for that one gauge.