I have a question about my 2013 4Runner. The other day the battery in my key died and my alarm was set. Luckily I had my wife's key so I deactivated the alarm and bought a new battery for my key. But how do I disarm the alarm if I didn't have a spare? I could enter the vehicle and the alarm would start chirping, but would I be able to shut it off and start it up?

 

Depends if the alarm is aftermarket or factory.
Do you have a bullhorn looking siren under the hood = aftermarket.
Do you have a button and light at the bottom of the dash = aftermarket.
Most alarms will disarm when the key is turned to on, but some won't.
Some will disarm if the drivers door key cylinder is unlocked from the outside, but some won't.
Just set if off and test it out.