I just bought a multimeter to do some tests on my car that won't start, but there is not much info in the operation of the unit.

What does "under load" mean in the instructions for using a multimeter?

Also, when using a multimeter to test wires and sensors on a car, does the battery have to be disconnected? I don't see anything about this in the instruction manual. It just says not to take resistance measurements on live electronic equipment.

I want to make sure I am not going to get shocked.