Q: Car won't start. Alarm keeps going off (aftermarket alarm)

Hello. From what you describe, it would appear that your vehicle has experienced some sort of electrical issues. It may be possible that the alarm system has been set off or has perhaps malfunctioned, and as a result is cutting off power to the vehicle. If the alarm is an aftermarket one, I would try to determine what model or type it may be to see if instructions can be located, perhaps on the manufacturer’s website.

I would also take a close look at the battery, especially if there are no lights or power coming on. There can certainly be cases where the alarm system, or even another system on the vehicle, experience a wiring issue, such as a short to ground, which can drain the battery. I would check to see if the battery is charged, and from there proceed to the vehicle’s fuses and relays, and then the alarm system.

If you are not comfortable checking this, a certified technician, such as one from YourMechanic, can come to your location to properly diagnose the starting issue.