Packard Forum Index » Pre-War (1899-1942)

when ignition is turned on,amp gauge goes to full negative, and of course when engine is running it will not charge. my sense is short. disconneted elec. fuel pump, no change,coil wire from ignition switch seems to be ok, any thoughts?

To get the amp meter to full negative without seeing smoke from an accessorie circut ? Maybe a shorted voltage regulator or generator, those are the only 2 circuts I can think of that can handle that amp draw.(with key on)

Going to ask the obvious question. Are you sure the battery connection or Amp Gauge connection are not reversed? Switched polarity will make the AMP gauge move to discharge as it's reading backwards.

could it also come from a disconnected ground wire either from the regulator,generator or whatever?

Usally not a disconnected ground (+). (Although there is a ground wire that connects directly to the frame of the voltage reg.)
I have only seen this happen when a regulators points stick closed on the field side of the regulator. This energizes the generator when the key is switched on ,turning the generator into a motor.In theory it might be possible for the armeture side to stick also,I haven't seen that.
Disconnect the regulator and see if you still get a large draw. I think you can find the diagnostic manual on this site for charging systems.

If my poor memory is correct,all the accessorie circuts run through the headlamp switch - if you don't find the charging system at fault this might be the next place to look. Use the search feature to locate a wiring diagram on this site.

ok, here's what I tried after finding the fault in the ignition coil or coil wire. I bypassed the ignition switch hot wired + to fuel pump,starter switch,cut the coil wire to the ig.switch and hot wired that together, bingo! works great also tried coil wire direct to the batterer y ,bingo,bingo. just don't know whether I should be doing this till I locate another Ignition switch .a little bit of knowledge is dangerous