Hi Guys I have a 87 iroc an in side the car in the back under the carpet where the wirer for the fuel gauge comes out are a pink brown an black I know the black is ground an the others are for what? my gauge is on full an there is a 1/4 of a tank could someone tell me how to fix it . Thanks

 

Sending unit in the tank is probably bad. You can use an ohm meter to read one of the wires to ground and you should get from 0 to 90 ohms for a good sending unit. 0 is empty and 90 is full I think.

 

When the gauge reads full like that, usually the ground is bad. Try cleaning rust or dirt off under the eye in the ground wire and making sure the screw is tight. If that doesn't work,the pink wire is the signal from the sender. Test resistance from the pink wire to ground. 0 is empty and 90 is full. You will be looking for something in the 15-20 ohm range for 1/4 tank.

 

I have checked the ground an it is good the pink an ground together an the gauge goes to empty when you take the ground off the gauge it pegs full. This is under the driver side trim pink black an tan what is the tan ? from under the car their is a purple orange an black off the tank this is a carbureted car. Thanks.