Fuel Level Sensor

The fuel level sending unit contains a variable resistor (track). As the float moves up or down, electrical resistance will change. To test the gauge sending unit only, it must be removed from vehicle. The unit is part of the fuel pump module. Refer to FUEL PUMP MODULE under FUEL SYSTEMS in REMOVAL & INSTALLATION - GRAND CHEROKEE article. Measure the resistance across the sending unit terminals. With float in up position, resistance should be 20 ohms (+/- 5%). With float in down position, resistance should be 270 ohms (+/- 5%).