Burnt Wire
Two of the fuses are hot at all times. This includes tail lights, brake lights and dome light.
Two or three are hot when the key closes the 'accessory' circuit. This includes Turn signals and heater.
Instrument lights are a subcircuit fed from the headlight switch.
Could the voltage regulator be bad causing the -40 discharge?
A 40 AMPERE discharge with the key off is a short to ground before the key switch.
You need to observe
when the ammeter moves, as well as how much and which direction.
Look at where the ammeter is placed in the circuit (see diagram above).
The ammeter shows current
flow out of the battery (Discharge), or flow into the battery (charge).
Key off, lights off, there should be no current flowing either way.
