6G Celicas Forums

Hi all, I'm new to 6gc forums and joined because I need help. I have an aftermarket alarm in my Celica that was installed back when the car was first bought in 1997. The alarm is always on and it drains the battery. Every time I try to jump-start the car I charge the battery to the point where the alarm comes back on and it thinks I'm stealing the car and won't let the car turn over.I'm seriously frustrated and just want to uninstall the alarm but don't know how. I just want to be able to jump start the car and turn it on again. Any tips on how to uninstall an alarm?