Fuel Gauge Drops when Headlights are Turned On!

[Mountain GN]

I had my GN converted to the Poston GNX-style dash a few years ago, and since then, I've noticed that I lose about 1/4 tank of fuel whenever I turn the lights on! I've been driving the car a lot on long trips lately, so this is now starting to get very annoying.

Before I start ripping things out, does anyone know what I should be looking for? Is this a gounding thing, or is the resistance somehow affected when I hit the lights?

Any suggestions would be greatly appreciated!

 

[RmvBfrFlght]

Could be a ground problem. I had the same issue with a 1st gen Firebird years ago. Ended up being the dash cluster ground was not properly attached.

Drive during the day have plenty of fuel. Get out of work and its dark, wham, where did all my gas go? But it was back the next morning. Took a while to figure that one out.

RemoveBeforeFlight