More likely than not the problem is the sending unit. The sensor is a varible resistor with a very small range. From 5 ohms to 80 ohms. It's under the first aid compartment!(sedan) Very large socket!! OOPS!!! you said wagon. The floor covering in the rear floor must be removed to get to sending unit.
[Edited by M.B.DOC on 12-01-2000 at 01:09 PM]