Hello,

New to the forum. I have a 1990 4runner. 3.0 v6, automatic, 4x4. I let the battery discharge from sitting without being started. I'm trying to charge the battery, but the alarm starts sounding as soon as I attach the charger to the battery. I've tried to use the fob to disarm the alarm, but it isn't working. I don't know if it is a factory alarm or aftermarket. The siren is located on the upper left firewall near the brake master cylinder.

I have the negative cable disconnected from the battery now, and am going to fully charge the battery before connecting the cable.

Is there a procedure to follow to reset the alarm system after the battery is discharged? Any help at all is greatly appreciated.

Thanks for your replies.

You should be able to tell if it's a factory alarm by the sound of it. Most factory alarms use the car horn but aftermarket uses a self contained siren. Being that it's a 1990 it probably is aftermarket. If you look under the dash (might have to remove the lower panels) you should see what's called a "BRAIN". Usually you will see a bunch of harnesses coming out. Anyways once you find that...

Either:

Disconnect the siren, either at the brain or cut the wire all together if you don't want it anymore (I do not recommend).

Look up your alarm, look at your fob. Is it branded? Find out which model you have, there's ways of bypassing certain sensors.

Disarm, most alarms won't sound unless locked.

Otherwise I just say keep doing what your doing. Disconnect negative and positive terminals and charge your battery.

Thanks for the reply.

After further investigation, I determined by the wiring that it is an aftermarket alarm.

The hood has a switch on it. I had the hood raised, and the alarm wouldn't disarm because that switch was open (closed?). I closed the switch, hit the alarm fob, problem solved.

Definitely a brain fart moment...