Fuel Gage & Low fuel warning

[310-MAN]

With lots of fuel in tank, fuel gage reads empty & low fuel warning lite came on all of a sudden. Truck is 2001 3/4 ton HD ex cab short box. Don't know what fuse powers these gages. Any ideas???? Thanks in advance John

[Grass Cutter]

Mine had the same problem. Today we took off the truck bed and repalced the fuel level sensor at the top of the fuel tank. Upon examination there were peices of crap on the two sensors that travel the resistor bar. Also found the metal rod used to hold the float was extremly rusty. After replacing the sensor the fuel gauge in the truck seems fine.

2001 2500HD 105,000 miles

[More Power]

The resistive element inside the tank should read from 40 ohms at empty to 250 ohms when full. This element sends a variable voltage to the truck's ECM, where it interprets the value, then send a class II serial data message to the IPC (Instrument Panel Cluster). In other words, the IPC fuel gauge isn't operated directly by the tank sender.

You could measure the variable resistance of the tank sender (at the 0.35 ORN/BLK C2-57 & 0.35 purple wire C2-54 connection on the underhood junction block) before dropping the tank.

MP