How to Fix Car Alarm
Learn how to fix car alarm with our detailed step-by-step guide. Follow our easy instructions to get it done right.
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0 of 6 steps completedStep-by-Step Instructions
1 Step 1: Identify Alarm Problem Type
Step 1: Identify Alarm Problem Type
Determine if alarm won't arm, keeps going off randomly, or won't disarm with remote.
Automotive Electrical Troubleshooting Guide
Book on diagnosing car alarm and electrical issues
2 Step 2: Check Key Fob Battery
Step 2: Check Key Fob Battery
Replace remote battery as weak battery is most common cause of alarm issues.
Key Fob Battery Replacement
CR2032 battery multi-pack for car remotes
3 Step 3: Inspect Door Sensors and Hood Pin
Step 3: Inspect Door Sensors and Hood Pin
Check that all doors, trunk, and hood close properly and sensors are clean and aligned.
Contact Cleaner Spray
Electronic contact cleaner for cleaning sensors
4 Step 4: Check Car Battery and Connections
Step 4: Check Car Battery and Connections
Test 12V battery voltage (should be 12.4V+) and ensure terminals are tight and corrosion-free.
Digital Multimeter
Voltage tester for checking car battery
Battery Terminal Cleaner
Tool and solution for cleaning battery posts
5 Step 5: Reset Alarm System
Step 5: Reset Alarm System
Disconnect battery for 15 minutes to reset alarm module, or use manufacturer reset procedure.
Socket Wrench Set
Tools for disconnecting battery terminals
6 Step 6: Reprogram Remote or Seek Professional Help
Step 6: Reprogram Remote or Seek Professional Help
Try reprogramming key fob following vehicle procedure, or take to dealer/alarm shop if problem persists.
OBD2 Scanner
Diagnostic tool for reading alarm system error codes