Whats wrong with my car ???

[toqwik]

Ok, here's the deal.68 Charger ..Alt gauge shows 0 sometimes, then shows charging sometimes.  Has a new alt and voltage regulator.  other gauges work sometimes it seems, except for the gas gauge, which has never showed any sign of life.  WHEN you turn on the headlights, all the gauges slowly got all the way to the right, except for the no-life gas gauge.  whats wrong here

[KMPX2]

Check the wirers coming in at the main bulkhead . The alt. wire is a good size wire and tends to have problems (like melting)

[Chryco Psycho]

you either have a ground problem at the gas tank or the the sender could be bad , try grounding the wire to the tank & see fi the guage moves , the ammemeter will not always show a charge , if the battery is charged & there is light load it will sit in the center , also at idle the alternator may not be turning fast enough to charge the battery

[toqwik]

What would the headlights switch have to do with guage function?

[Chryco Psycho]

ti will change the load on the alt which could increase the actual voltage to the regulator , possibly the regulator is weak ???he

[Ghoste]

Doesn't help with this problem, but, in answer to the headlight question.  We once had a Jeep pickup truck for the farm and the next morning after using it, dad would always bark at me for burning up all his fuel.  I was puzzled because there was always gas in it when I parked it.  After fighting about it for several weeks we finally learned that when the headlights were on, the gas guage would read high.   I was borrowing it after supper.  Lot's of fuel then.  Drive around, put in some gas and drive around some more and then come home after dark.  Lots of fuel when I parked it at night.

[blackcharger]

and make sure the wires on the alt gauge are tight, and not corroded.
  Dave