fuel tank wires

[robinoz]

hi my petrol gauge isnt working and looks like the 2 wires on the tank are off and i dont know which goes where ive tried them on both ways but doent seem to work does the gauge only work when the engine is running ??
i started looking at this while investegating my other problem engine runs with the earth strap off and battery light constantly on and not charging its really starting to p*** me of now as i can leagely drive it agggggghhhhhhhhhhhh lol had my dummy spit now back out to have another look

[ChrisRLewis]

There are two wires Grey/Red (operates low fuel warning light) and a Light Blue/Yellow (operates fuel gauge) on the fuel tank sender.

The gauge works with the ignition on and you dont need the engine running.

To check the circuit..

First check make sure that the fuel tank is earthed, if there is no earth the gauge or the fuel warning light will not work!

You will need a long length of cable (test cable) to carry out these tests, connect the test cable to the battery earth connection.

Remove the two cables from the fuel sender.

With the ignition on and the two cables removed from the sender unit, connect the other end of the test earth cable to the Grey/Red cable that you have removed from the fuel tank sender,  the fuel warning light should now come on.

Try the same test for the other cable Light Blue/Yellow, this time the fuel gauge should go to full.

Report back your findings.

[robinoz]

tank is out of car and the float thing for the wires is out of the tank does this make a difference to the testing and is the tank suppossed to be earthed when in the car if so how?? cheers for the way to test it will do that tommorow as its night here now

[ChrisRLewis]

tank out of the car does not make any difference to this test.

[robinoz]

just done that test all wires working but i think the floats had it fuel warning light is on and theres plenty of fuel gauge moves upto empty when ignition on so i will order a new float and fuel sender if thats what its called
the prob was the underseal on the car was preventing the tank from making a earth
thanks for the info