Mopar friend in PA needs help

Yes.
I walked him through that step, best as I could.
-Disconnected bulkhead connector and cleaned from the engine side, (no obvious corrosion visible).
- Tried wiggling bulkhead from underside of dash, with no changes.
- He was able to disconnect and bolt together ammeter connections, still no change.
- And when the car decides to "start and run" he is getting about 13.5 volts across the battery.
Thanks.