Pontiac Repair: Security/Anti-Theft Module, dash light, inconvenient times

Question
Hey Todd,

The wife's 01 Grand-Am's security module is acting up.  Periodically it goes into lock-out mode (at the most inconvenient times of course).  After the dash light stops flashing (10 mins) it fires up and and she's OK for a week or two.  The local wrecker wants $18.00 for a used one with a 90 day warranty so I want to try that approach 1st.
Question, where is this located, what does look like and what is the "re-learn" procedure to adapt the used one to my wife's car.

Thanks,

Answer
Hi Colin:

it could bea few things the BCM which is the theft module on this car could be getting water in it. the HVAC module leaks water onto the module and causes issues. the BCM is loacted under the hvac module under the glove box. I would check the 3 connectos there to make sure there is no corrosion in them. if they are clean then chances are it just needs an ignition lock housing assembly. the sensor in the module goes bad. DO NOT GET A USED one of those. as for the BCM they are not reusable once they have the VIN set in them from the car they are in they will only work in that car they can not be used in another one. the sensor in the lock hosuing skews hi or low and the BCMN doesn't like what it sees so it will not allow the car to start. when you relearn it your learning it to the new swewed reading it's good untill that readin skews some more and they your stuck again. good luck :-)