[bbcngineer]

Guys,

I have read the existing step by step diagnostics in the archives. I still cannot figure this one out. My car is a 72 Chevelle. When I try to ground out the gauge it will not go to empty until I turn on the lights. Once I turn the running lights on the gauge goes to empty. When this is not grounded the gauge reads half past full all the time it makes no difference if the key is on or not. I have run a 12 volt jumper directly to the sending unit, it does not change. I have also jumpered the ground to a known good ground. Any ideas before I drop the tank?

bbcngineer

 

[rick]

Have you tried this: http://chevelleengineer.home.comcast.net/fuelgage.htm Worked very well for me.

 

[bbcngineer]

Guys,

When I ground the tan wire the gauge does not go to empty unless the dash lights are on. Does this mean the gauge is using the light circuit to make the ground connection?

bbcngineer