Two days ago I had the heater on as I drove to a coffee shop. When I arrived, I parked my car, turned off the engine, pulled out my key and entered the coffee shop. I had to do some work with my laptop.

Three hours later I was done with my work and left the coffee shop. I got into the car but it would not start. It gave me the "Check charging system" sign. From the sound of the ignition, it looked like the battery was dead (however, it's not an old battery).

Anyway, I decided to ask someone for a jump and the car started immediately.

I have not driven it since that incident. I plan on driving it later today. Hopefully, it's fine.

My question: Could the fact that I did not turn off the heater have caused the problem? I thought that if the engine was turned off the heater was also turned off. Or was I wrong?

 

Year of car, hybrid?

Charging system icon was on?

Unless something strange as a stuck electrical relay the heater motor should turn off with ign key off.

At one time Toyota had some cars where an electrical issue was causing the blower to come on with ign key off/out, doors locked, etc.