35 Ford Ammeter Flops to Full Discharge

[Road Journey]

Stock 35 Ford, 6 volt. Ammeter started instantly flopping to full discharge (-) when ignition turned on. Car cranks, starts OK & when engine running ammeter indication normal, charging.

What's going on? Thanks.

 

[Brian]

Sounds like the cutout is stuck shut

 

[Bob C]

Looking at the wiring diagram the only thing the ignition switch supplies
is the coil and oil pressure gauge.

 

[Kerk]

!!! DISCONNECT THE BATTERY A S A P....I have lost 2 1932 AMP METERS AS i WATCHED THE GAGE MELT OUT OF THE GAGE when the points stuck on the cut out ! JME kerk could start a fire possibly

 

[JSeery]

A 35 should have the loop style ammeter shouldn't it? No way that should be an issue. Need to do some detailed looking into the wiring, nothing should be a large current draw with the ignition switch being turned on. Turning the switch on connects to the ballast resistor and coil and to the oil pressure gauge. A large current draw would require a short somewhere in the ignition circuit or the oil pressure gauge. It is also possible that the wire through the ammeter is going the wrong direction, showing discharge when it is charging. Sounds like the whole system needs to be checked over and the cutout check.