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Q: Alarm system stays on.

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Changed the thermostat and had to remove alternator by disconnecting negative battery, after everything was replaced and negative battery post connected and alarm system goes on and my key no longer works on door lock to deactivate the alarm and Jeep starts for a few seconds then shuts off.

My car has an automatic transmission.

Hi there. Anytime electrical components are repaired, serviced or replaced, it’s best practices to remove both the positive and negative battery terminals. The negative terminal is a ground that allows the circuit to complete. It’s possible that while removing your alternator that an electrical signal was sent to the ECU and may have caused damage or created an error code that has disabled your ignition system or anti-theft system. You should have a professional mechanic complete a check engine light inspection to determine if there are any fault codes, have them reset and see if the issue clears up.

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