YES!
My version:A bad relay switch that goes bad can "stick" in the on position and leave what ever it powers on and drain the batteryYou should be able to see the item that is on.
yes
the a\c clutch for the compressor is probably staying on when you turn the car off. It could be the ignition switch. or a bad relay.
No, a bad ground will not drain the battery. A dead cell in the battery will most certainly drain it. If it has a dead cell it must be replaced. Also any light that is on will drain it. Lastly a stuck relay will run it down.
No, a bad coil will not drain the battery.
Yes possible. If switch does not open on engine shut down battery will drain If switch does not close on start up battery will not charge
bad ignition switch, bad battery, bad alternator/regulator,
Could be,low battery, loose or dirty battery connections, starter is bad, starter solenoid is bad, neutral safety switch bad or out of adjustment, starter relay is bad,
Good possibility
Bad Starter. Bad Starter Relay. Bad Ignition Switch. Bad Ignition Module. Improper Ground.
The door lock relay is bad and is causing your voltage drain. Relay needs replacing.
Low or bad battery. Bad connections on battery posts. No connection through the ignition switch to the starter relay. Relay defective. Cables loose. Starter bad. A simple voltmeter is very helpful on these repair problems.
best way to test a relay is remove it from board, get a 9v square battery and touch the switching terminals on the relay, the relay should click if its working. You can then test resistance through the relay. You can also check the feed to the relay, if theres pwer to the switching terminals on the relay, chances are the switch it ok. If no voltage, switch or wiring.