Test B: Incorrect Fuel Gauge Indication

PINPOINT TEST B: INCORRECT FUEL GAUGE INDICATION

B1-B3:

B3-B6:

B6-B9:

B9-B11:

B12:

Normal Operation
The fuel tank is a saddle tank design with variable resistance senders, driven by floats, that provide resistances related to fuel height, in each side, to the instrument cluster. The fuel level is determined using a variable resistance fuel sender unit, with an approximate resistance range between 15 ohms ± 2 ohms at empty (E) and 160 ohms ± 4 ohms at full (F). The fuel sender is hardwired to the instrument cluster through the signal circuit 29 (YE/WH) and the return circuit 1843 (BK/OG). The remote fuel sender is hardwired to the instrument cluster through the signal circuit 1356 (LG/VT) and the return circuit 1357 (LB/YE). The instrument cluster monitors the resistance readings that are sent to the instrument cluster from the fuel senders and commands the fuel gauge with a corresponding movement of the pointer. If the remote fuel sender is open, the fuel gauge defaults to the fuel sender value only and the fuel gauge indicates E to 1/2 tank. If the fuel sender is open, the fuel gauge defaults to the empty position.

Possible Causes
- circuit 29 (YE/WH) open, short to ground, or short to voltage
- circuit 1356 (LG/VT) open, short to ground, or short to voltage
- circuit 1357 (LB/YE) open, short to ground, or short to voltage
- circuit 1843 (BK/OG) open, short to ground, or short to voltage
- fuel sender
- remote fuel sender
- fuel tank and/or lines
- instrument cluster