A quick way to determine if the gauge (idiot light) or sending unit is faulty
is to disconnect the sending unit electrical harness and ground it (if two terminal,
jumper between the terminals). If the gauge responds, the sending unit may be
faulty. Proceed with the sending unit test.
- Disconnect the sending unit electrical harness.
- Using an ohmmeter, check continuity of the sending unit terminals (sending
unit terminal and ground).
- With the engine stopped, continuity should exist.
- With the engine running, continuity should not exist.
- If continuity does not exist as stated, the sending unit is faulty.
