electrical/guage problem help needed

[charge-it]

A new problem showed up on my 68 Charger. My fuel guage, water temperature guage and oil pressure guage work fine until I turn on my headlight switch. When I do, those three guages peg themselves. Before digging into it has anyone expirienced this before? Is it a headlight switch problem, dash dimmer switch problem, or a problem with the plug in voltage limiter on the back of the guage panel? I'm not the greatest when it comes to these types of problems and any help or suggestions would be helpful. Thanks

[A383Wing]

I say it's a ground problem either at the cluster pin connection or possibly the pins are loose at the circuit boards

[doctor4766]

I know that if the ground wire has come away from the voltage regulator on the back of the cluster all the gauges will read flat out, but I'm uncertain as to why it happens when you turn on the headlights