I'm having a problem with my autometer a/f cobalt gauge, it works fine than when I turn on the backlight the rich/lean goes off and all that is on is the blue. All the wires are hook up like the instruction says, anybody?

 

still hooked up wrong! wire it into your radio fuse! and those are worthless just a pretty light show. you give it gas and it goes up, you let off and it goes down!

 

A/F guages are pretty much a waste of money. You won't have any sort a accuracy or numbers to even determine what your air/fuel ratio is. Like bottlefed said, a pretty light show.

 

mmmmm....... light show