Chevrolet Repair: security light, measure resistance, oxygen sensor

Question
QUESTION:  had problems with the cooling fan on my 95 camero V6 3.8
I changed the sensors and the cooling sensors also the oxygen sensor the fan is working now but when you start the car its fine you shut it off and remove the key it buzzes and the security light blinks how do i stop this?
Thank you
Victor Haley

ANSWER: Hey Victor,

 Does not sound related. Lets address this problem as if it is a new symptom. Does the car have a factory VAT1 key? (pellet in key)

wayne

---------- FOLLOW-UP ----------

QUESTION: Wayne, the car has a chip in the key and I have two different ignition keys one that is used all the time the other is a spare I have tired both and get the me results.

Answer
Ok well here is your possible solution:

 Remove the lower panel under the column and follow the harness to where it goes into a rectangular junction block.  The two smallest white wires with an orange sleeve are the VATS1 wires that are used to measure the pellet in the key.  Put an ohm meter on these two wires and they should be open.  With the key in the ignition you should will be able to read the resistance of the pellet on those two wires.  Now keep the meter on the wires while you TURN the lock cylinder and monitor the resistance.  This is usually when they fail and the computer loses sight of the key.  There are 3 ways to fix this if that is the problem.

A: New lock cylinder and key
B: Measure resistance of key and purchase resistor from electronics store and wire parrallel into circuit.
C: Go to dealer and purchase VAT1 Blank key.  They will stick your key into a machine that will give them the code of the pellet (resistance) and sell you the blank.

 I can guide you through the rr if you want.

Wayne Howie