# Passlock

**URL:** <https://community.cartalk.com/t/passlock/18248>\
**Category:** Maintenance/Repairs\
**Created:** [August 16, 2008, 12:22pm UTC](https://community.cartalk.com/t/passlock/18248 "2008-08-16T12:22:18Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![petermauro](https://avatars.discourse-cdn.com/v4/letter/p/49beb7/32.png) [@petermauro](https://community.cartalk.com/u/petermauro)\
**Post date:** [August 16, 2008, 12:22pm UTC](https://community.cartalk.com/t/passlock/18248/1 "2008-08-16T12:22:18Z")

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Dear Tom & Ray,  
  
  
  
 General Motors has a anti - theft system called:  
  
 " Passlock "  
  
  
  
 It uses a signal from the ignition switch,  
  
 fed into a electronic box under the dash board,  
  
 which stops gas flow , if the signal is absent.  
  
 I’ve found a method of defeating this system, should it be defective , because of a bad ignition switch.  
  
 It requires cutting the ignition switch wire,  
  
 while the engine is running, causing the system to fail enabled. And, that condition will remain enabled , as long as the battery is connected.  
  
 I’d like to duplicate that signal , comming from the ignition switch , so I can replace the battery when necessary.  
  
  
  
 What is that signal?