Here are the symptoms:

Note that these only occur when the instrument panel dimmer is turned 'on' (any position other than 'off')

Fuel gauge reads high

Temp gauge reads high

High beam indicator glows

Both turn signal indicators glow

Instrument panel lighting dims

The lights flicker and glow randomly while the gauges act too slowly to reveal any such drama.

Initially I suspected the voltage regulator was acting up but once I discovered that all the gauges functioned properly when the dimmer was off I began to reconsider my initial hunch.

The wiring diagrams revealed that indeed all these devices share the same ground (in the case of the gauges it is the voltage regulator's ground). If the ground line took on a slightly positive voltage then all of these symptoms would be present. So my question is this: How the heck am I getting a floating voltage on the ground line when I turn on my instrument panel lights?

Could one of the light bulbs be messed up? I see 3 bulbs on the diagram but I only know of the two top bulbs, where's the third? If I had two good bulbs and one that, for some reason, had almost no resistance what would happen? Would I have voltage on the ground line?

Thanks in advance.