Does leaving your key in the ignition, even when off, drain tbe battery?

[steved0x]

I've got the car on jackstands as part of a coolant flush/wp/thermostat/udp installation. The other day when I drained it I had the key in the on.position to run the heater per the 101 projects guide. When that was done I shut the key off, but left it in the ignition. Today my son heard a beeping/clicking so he took the key out. This evening I inserted the key and turned it one click to the right and got very dim dashboard lighting that flickered in time to a bunch of dead battery style clicking... When removing the key the odometer and a few other dash lights remained on very dim.

Does leaving the key in drain the battery, perhaps by keeping some interior lighting on? Or might it be something else? (I am certain the key was off because the most recent thing I did was run the car for about 30 seconds to try and use the water pump to expel.coolant out of the disconnected thermostat hose while I added distilled water to the coolant tank which didn't work by the way ) and so the key was turned off to shut the car down.

I want to drop the top for greater access when accessing the engine behind the seats, can I do that by using jumper cables and another car?

Thanks.

Steve

[Chuck W.]

Yes, it does. I too learned the hard way.

I can't see a problem using a jump to power the top.

[steved0x]

Cool, my son got a jumper thing so we are going to try it tomorrow. Thank you.