The car alarm shorted out, and not I can't start my car.
I’ll assume that you are speaking of an aftermarket alarm. There is a huge selection of alarms on the market and they all have different features for making the car more secure. Most have a starter interrupt relay. The start wire from the ignition switch is cut and routed through the alarm. The alarm has to energize the start wire. If it shorted, whatever power source was wired to it blew a fuse or fusible link. The establishment that installed it will be the most familiar with it. The other option is to remove it and splice all of the circuits back to original condition. If you would like assistance, a certified mechanic from YourMechanic can inspect your car's electrical system to determine what is causing the no-start.
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