We have juice to the lights.
No juice to the starter.
Lets work backwards:
If there WAS juice to the starter, AND the battery cable connection was bad, then just trying to start it would finish the disconnect there would be no power...
For now, battery connection seems ok
IF there is power to the starter solenoid, the starter solenoid should clack or click
-solenoid does nothing.
IF the solenoid does nothing but is otherwise energized in the start position and it's seized, it would very much dim the lights.
-lights don't dim
So this means:
the solenoid connection is compromised,
OR-the solenoid is bad within itself, burnt contacts or broken inside,
OR-the solenoid may broken---it happens, and this will result in a totally dead key--
chapsolenoid.jpg
OR- the solenoid isn't getting power at all in the START position.
This means some voltage tests need to be taken.
On the solenoid, first check the battery LINE IN wire, it's the broken one in my pic. The one directly below is LOAD OUT to the starter motor. The LINE IN should ALWAYS have power, as it should be directly connected to the battery.
IF no volts, THEN check the battery to starter wire and connection(s)..
IF yes volts, then:
check the low amp 'trigger' wire for power with the key in the START position. If there's 2 low amp wires, one will be ground, If no power on one, check the other.
IF no power on the trigger wire,
THEN- either the wire or connection is faulty,
OR the starter relay is faulty,
OR the ignition switch is faulty.
When it gets to this point, finding which relay is the starter relay and just replacing it is the easiest way to troubleshoot, UNLESS you're willing to figure out which wire is the starter HOT wire off the ignition switch in the jungle of wiring under the dash. If you are and can find it, it should show volts in the start position.
As for your drain, it sounds like driving it doesn't charge the battery, meaning bad alternator or voltage regulator. You could also have a faulty stereo's memory eating too much power, or maybe a light is on somewhere all the time. My wife's Mustang's GPS display decided to not shut off one day. I've pulled it's fuse AND the main power plug an it STILL draws power constantly because the memory input is separate.
Anyway, car electrical issues suck, good luck!