My fuel gauge drops by 1/4 of a tank when I turn my lights on. I am guessing a ground wire problem, but I don't have a wiring diagram (yet) and I don't understand the connection between the light switch and the fuel gauge. Can anyone help?

I'd try a jumper wire from meter ground to a good dash ground and see if that prevents it from moving.

The ground for the speedometer gauge pod is mounted through the upper center screw that holds the main front bezel in place. You can see the screw while sitting in the drivers seat but the ground connection is behind the bezel. Try tightening the screw first and see if that does it. Sometimes there is corrosion built up between the ground strap and the steel dash frame that will require lowering the pod to clean. Usually just tightening the screw will work.

I think that center screw ground is only for the high beam indicator. The ground wire for the guage pod is connected to the steering column.

Kyvox,

Check out UPC 12 Sheet B3 (Page 162) in the 1968 AIM.

It shows a ground strap from the high-beam indicator to the steel gauge housing.

There was no steering column ground attachment on my '68.

Do the '67's have a different ground, or is there another ground that may have been eliminated sometime in the cars' past?

Carl

The ground wire is shown in UPC 12, B2. It connects to the pedal bracket. Apparently, the addition of this ground wire was a mid-year modification, as noted in the revision record. May have been due to the problem your talking about of the center screw comming loose. Your right though, there is a ground strap to the housing. 67 AIM shows the same drawing as 68 on B3.

That's why. Mine is an October '67 build, hence no ground wire.

Thanks for the heads up

Success! graemlins/hurray.gif My top center bezel screw was missing. I replaced it and my fuel guage now apears to be working correctly. The previous owner must have been attempting a cheap weight reduction program, because I have noticed a lot of missing/mismatched fasteners ;) . Thank you all for the help, now it is time to find out why my horn does't work!

Hmmmm... maybe that's why my Fuel guage is off 1/4 tank (reads high) and my Speedo isn't working. (The center screw was missing.)