Simple Test
Disconnect fuel sending unit connector wire in luggage compartment, cargo space, or at tank unit. Connect a 12-volt, 3.4-watt bulb to harness side of connector, between power terminal and ground (Yellow and Black wires on Montero). On Pickup and Ram-50, see Fig 1 . Turn ignition switch to ON position. Ensure test bulb flashes, or stays on, and fuel gauge needle moves. If bulb or gauge needle does not function as described, check and repair fuel gauge circuit.
CAUTION:
Gauge coils can be damaged if wire is grounded too long. Perform test as quickly as possible.
NOTE:
The following test must be completed with instrument panel cluster removed. Use ohmmeter for all measurements. If resistance is extremely low, there may be a short in the coil. If resistance is extremely high, there may be a broken wire or similar problem in the gauge.