Battery draining overnight
My favorite way to troubleshoot battery drains is to use a small bulb like a dash light. Get one with leads. Unhook your positive battery cable and put one wire on the unhooked battery cable and the other one to the positive battery post.
If you have a drain, the battery will light up. Unhook stuff till the light goes out.
To add to this.......sometimes there are other things "on" or a large enough draw that the small dash lamp is very bright. Or the opposite, not enough to even light it.
So.........what to do?
Along with the dash lamp, also "rig" an old tail/ stop bulb and socket. This gives you several combinations. You can wire the two filaments in parallel (twist the tail/ stop wires together and use the lamp shell) for a large wattage test bulb
Use the lamp shell and the stop filament for a slightly lower wattage,,
Use the lamp shell and the tail filament for less yet,
Or use the two wires and leave the shell unconnected, which pust the two filaments in series, for a 'smallest' wattage.
AFTER you get the drain down to the dash lamp, or a "glowing" dash lamp, you can if you like, put your multimeter current (ammeter) in series with the ground, and find out how large the draw is.
