2000 blazer ignition

Hi, I would like to install a "custom" immobilizer on a 2000 blazer, independent from any alarm, and switchable from a discreet interrupt or even from a remote.

I plan to intercept the ignition. Please any ideas on how to do this?

thank you!
drevel

A 2000 Blazer is already equipped with the GM PassLock II vehicle immobilizer, which changes the R-Code (resistance value) from the ignition switch and the BCM every time the truck is started, so you will have to get pretty fancy to go above and beyond that.  I wouldn't recommend doing anything under the dash, like a typical relay-based starter kill for instance, because anyone good enough to bypass the factory immobilizer is definitely good enough to reconnect a starter wire that is cut in half.

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thanks for the response,

really I'm thinking about intercepting it discreetly in the engine, I think as long as we do something "not standard" there will be more difficulf for the thief to start the engine. To start it, he must be a blazer electrical expert to recognize where the interception might be, and have a lot of time...

should it be possible to simply intercept a wire preventing the car to start?   the fuel pump as passlock II does, the sparks, or may be another

regards
drevel

I would recommend some kind of starter solenoid input interruption in the engine bay---possibly controlled via a well-hidden push-button switch (Pushed while cranking) and a relay such as this:

Switch wire #1 : GROUND

Switch wire #2 : TO "85" on relay

"86" on relay : Ignition 12V+

"30" on relay : Key switch side of starter wire

"87" on relay : Starter solenoid side of starter wire

The relay should be located under the hood, so as not to cause too much resistance or risk grounding anything out, and the button could be virtually anywhere within reach of the driver's seat.

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I have yet to see a "rolling" passlock system. It is a fixed value resistance in the key chamber, inserting the key completes the circuit. If the resistance rolled each time the vehicle started, how did the older dipswitch Passlock modules work????

Gus


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Wherever I go, that is where I end up......

You may be correct about the fixed resistance value... I have always thought it was "rolling" though since in the 555L manual, the Passlock II system description states that "When the key cylinder is properly turned, it generates the R-Code..." and "If the R-Code is incorrect, the vehicle will start for a moment and then shut off."  This led me to believe that the ignition switch sender generated a different R-Code of a different resistance each time, and thus was the reason GM changed from Passlock I to Passlock II in the first place, as added security.  Hmmm.  Now I am inclined to know for sure.

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Passlock 2 is actually simpler.... no bulb check wire. Wonder what happens once the bulb burns out? Car probably won't start..... hee hee.

Before all this fancy self learning stuff, we used to cut the yellow, measure, and set a series of dipswitches on a bypass (or, used a coupla relays and a resistor value). This worked fine and dandy..... if you were within less than 3% or so of the measured value, no problemo. If you were (or your meter was a POS) out a bit more than that, well.... key chamber resistance changed when it got cold (-35C cold... none of that -5F that people think is cold), and no start. WHeeee. 555L simply learns the resistor code everytime the car is started with the key, rather than being set up once. Kepps things a little more foolproof in the long run. Still don't really trust these allin one bypasses that do locks, pass, everything. If you have to make a device learn something, chances are, it can forget that very same thing. Things that learn all by themselves don't need babysitting.

Gus


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Wherever I go, that is where I end up......