Jon I have mornings like that but they seem to happen more often as I get older.
Oldbolter. Go back to your troubleshooting steps after the problem occurred.
You unplugged the fan and checked voltage at the battery. What was the voltage?
Then you checked the voltage at the fan connector and read 16.2 volts. Was the engine running?
On a one wire alternator, I don't see a problem with connecting a fan circuit as long as it is properly fused.
Many use that point to supply headlight voltage via a relay contacts (shorter wires - less voltage drop).
Were you having any electrical problems before you installed the radiator and fan?
