Silly gage problem

[solidfrontaxle]

On my 76 55 sometimes when I turn my headlights on, my temp guage either a)goes up to the near overheating range, b) stays the same, or c) drops down to zero. Sometimes my fuel guage will change levels too.
Its not a big deal, just kind of weird. The headlights don't have relays so I know that circuit sucks alot of juice through the switch, but according to the wiring diagram, the dash gages aren't even on a related circuit. I can turn off my headlights and the temp drops back to normal and if I turn them back on again the temp gage will randomly decide to do one of the three choices.
I figure if I ever get around to doing a relay conversion it will likely solve the problem, but my stock headlights are blindingly bright, which is weird in itself considering its a land cruiser and the other wiring gremlins I've got. The blinker barely has enough voltage to work at idle.

 

[Pighead]

I don't know why, but I'll bet it's a bad ground. or two.

 

[cruiser_guy]

I don't know why, but I'll bet it's a bad ground. or two.

That's the most common electrical problem and when fixed, it fixes alot of issues!!

 

[solidfrontaxle]

So where would the grounds for these circuits be located?

 

[cruiserbrett]

check any white with black stripe wires. locations vary, but color code does not. clean these connections and report back.

there is a voltage regulator on the back of the instrument cluster that might be the culprit too.

 

[cruiser_guy]

The negative wire from the battery needs to be clean at the battery end and the ends at the engine, body and frame. The engine, body and frame should all be electrically connected with heavy gauge wire.