Posted 05 January 2010 - 06:16 PM
The following values are nominal extremes.
Full = 10 Ohms
Empty = 270 Ohms.
The actual range will vary from sending unit to sending unit. A more reasonable expectation would be a range from 240 Ohms = empty to 33 Ohms = full... which is an industry standard.
If you suspect your sending unit is bad, the easy test is to jumper the two sending unit terminals together with a short piece of wire or a paperclip. With the terminals jumpered, turn the ignition switch to the run position. If the gauge goes to full, the gauge is OK. Anything less than full indicates a problem elsewhere (gauge, voltage stabilizer, corroded earth connection, etc.)