Voltage drop issue- where to go from here

[67Dart273]

Without knowing what all you are doing, this is tough. Is the battery disconnected? I've forgotten "what all" and "where all" you've been

The black wire to the ammeter (speaking her of factory wiring) comes off the ammeter --goes through the bulkhead connector -- and to the output stud of the alternator. DEPENDING ON which way you have your ohmeter (it has a battery) you will trigger the alternator diodes "forward biased" and gain a path through ground..

This ground path MIGHT be what is causing your reading, "coming back" from ground up through one of the loads on the blue wire

The blue is IGN1 often called "ignition 1" This feeds lots of stuff, depending on the year, and IS NOT FUSED

On earlier cars, it feeds power to the dash gauges through the instrument regulator

the dash cluster warning lights ---oil, brake, etc

and branches off, goes out through the bulkhead connector and feeds the ignition system and IGN terminal of the voltage regulator

70/ later, depending on years, this IGN1 also feeds the alternator field (blue) and some smog doo - dads, like, idle solenoid or advance retard if used, etc.

The ignition switch ALSO gets it's main power feed, as does the fuse panel "hot buss" off that same black ammeter wire.

Here, read this:

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

and the diagram down the page:

........gives you a good idea of power distribution in these cars. You can see the "welded splice" in the black ammeter wire. This is a factory welded splice a few inches from the ammeter, up in the dash harness, and branches off and feeds several things as indicated. THIS IS NOT FUSED. The headlight switch has a breaker in the switch.

 

[Viper21700]

Ok dart,
Heres where I sit. Dashboard has been pulled out, battery removed. All connections to the dash disconnected. Ignition switch disconnected. The only switches in the dash that are connected are-
Headlight switch
Wiper switch

In the engine bay, I disconnected two lower wires from the ballast resistor. One goes to the V.R. on the firewall drivers side. One runs into the cabin. I BELIEVE this is the wire running to the I1 (Dark Blue, but has been partly replaced with a red/gold wire, no bulkhead connector in this car as it was removed and direct spliced at the bulkhead)

According to my schematic, it looks like I1 is a direct feed to the ballast resistor.. But I am at a loss to why Im still getting continuity through it. Does this wire tie into the welded splice?

 

[67Dart273]

Like I say, the black goes to the ammeter. First thing to do is swap the probes red for black on your ohmeter and see if the reading changes

 

[Viper21700]

Well replaced the entire wire from the ignition switch today, previous wire was 16 gauge, had a roll of green 12 gauge in my shop. Rewired it, granted its not the original color, then went and updated my printed out copy of the schematics with the correct color... Eventually when I'm done that schematic is getting laminated and stashed in the truck roflmao. Next weekend I should have the old girl started back up and running hopefully. Been a long couple months with little to show.

Oh and the dark blue wire labeled as I1 (or T) on the ignition switch is a direct run to the ballast resistor.