I used tunercat and turned off the VATS security checks... still getting the occasional "security" light. I think the previous owner had a vats bypass on the car, because i was able to start it up even after swapping columns.

I did pull the chip out of the old key and solder wires to it to appease the security light... but noticed the security light would still come on time to time.

Any way to disable it completely besides pulling the bulb?

 

The Theft Decoder Module (TDM) does three things, sends a 50HZ signal to the PCM to allow injectors to pick (this can be disabled with PCM programming), it also lights up the Security lite and it picks the Theft Deterrent Relay (TDR) that allows the starter solenoid to pick. If the key resister is bypassed it should allow the TDM to think all is normal when the IGN is turned on. If starter is kicking over the bypass is working , you may be getting noise or something starting the security light timer in the TDM and lighting the indicator. The lite is turned on by a ground signal from the TDM. If you have a wire diagram for your car try opening the line from TDM to indicator to disable it . ref shbox http://shbox.com/1/pass_key.jpg

 

Thanks, that exactly what I was looking for. Hopefully easier than taking the dash apart to get the bulb out.

Are you familier with tunercat? I've only found a couple places where VATS is mentioned... i unchecked all 3 spots I could find. I'm wondering if I'm missing something. This may be more of a question for programming section. I found 3 switches under the "ECM TABLE" that refer to vats... but think they may just be refering to whether it will throw a code or not.

 

Since it is the TDM (not the PCM) that controls the security light, there is nothing you can program in the PCM to bypass the light.

Perhaps your connection for the key pellet is coming loose at times.

 

Postalbunny, Sorry I do not have any practical experience with disabling VATs via programming w/TunerCat. As you mentioned there are 3 settings in the switch table F-body enable, y-body enable and diagnostic error code 46 enable. However if you have the pellet bypass then the TDM should be sending 50HZ signal to the PCM and no programming is really necessary. In reality programing is only needed if you remove the TDM (50HZ signal to PCM) or decide not to use it any more. In that case you would also have to jury-rig a pick signal to the TDR the get the starter picked and also kill the security lite indicator circuit . Or you could buy a TDM bypass unit off of e-bay that simulates the TDM. Your OP mentioned the previous owner had VATs bypassed, did he/she bypass the key pellet only, bypass the complete TDM with a bypass module, or by-pass it by re-wiring the TDR pick and programming the PCM , or a combination of all the above.

 

I know they didn't do a pellit bypass because the security light never came on until after I swapped columns (and keys). But the car still started, just gave me an instant security light. I did find the start bypass relay, but didn't notice anything related to the TDM etc... but did not know what to look for.
Looks like i'll need to pull underside of the dash and exam everything closer. Don't want to end up stranded later in life due to a jurry rigged vats system.