Everything in the electrical system runs on twelve volts. (Voltage is electrical pressure). Computers in particular are very picky about having proper and steady supply voltage. Many will become confused and start to do weird things, or they will just stop working when supply voltage is low. Airbag computers need to supply a sudden jolt of current when they need to fire an airbag, and they cannot develop the needed current if they do not have sufficient voltage. Anti-lock brake computers need to run the valves that control brake fluid flow. Those do not work right if the solenoids are not supplied with sufficient voltage, and the computer knows that, so it will shut the system down and turn on the yellow warning light to tell you. The engine computer has to run the high-current ignition coil(s) and injectors. It cannot do that properly if voltage is low. Your radio also has a computer in it. The circuitry is designed to work correctly when supplied with a minimum of twelve volts. Below that, things begin to stop working.
Instead of worrying about the things that cannot work with low voltage, take care of the cause of that low voltage. If the battery is bad, replace it.
Thursday, December 22nd, 2016 AT 1:38 PM