i replaced the sending unit and gauge always shows full. take out and move and only goes to half when pushed all the way down. somebody told might be the ground? what colour wire is that? thanks

 

Fuel tank module (diesel) - lt gray 4 way cav circuit function
1 - -
2 k4 20bk/lb sensor ground
3 k226 20db/wt fuel level sensor signal
4 - -

 

i am not really sure if i understand your language there..... could you explain better?

 

connector at fuel tank module, clean and check all grounds off the PCM. Run ground to #2 at tank connector see if gauge reads properly then. Check resistance of #2 terminal at tank connector. You can also do a instrument cluster test by holding down trip reset button and then turning ign to on position, will check for proper operation of gauges.

 

i cleaned all the contacts you mentioned. should i check the ohms at the sending unit contact 2 at 20 ohms on the multimeter? that instrument cluster test was pretty cool

 

Guess it has something to do with the sending unit.Im on the same boat a week ago or so. The difference was that my auto was totally deteriorated and thus i replaced some parts that deals with electrical aspect. recommend doing the same thing for $40-$50. Just search the specific edit to remove non-sponsor vendor link you need using your fav search engine and lots of them will appear...hope this little knowledge helps