Car Alarms: 2000 Silverado, silverado truck, passlock ii

Question
My 2000 Silverado truck used to have an after- market alarm and remote start, but I had the dealer remove it after the truck would give false security shut-downs for no apparent reason.  That helped for awhile, but the problem is back.  Occasionally, I will try to start my truck and it will attempt to start, but immediately die.  The security light flashes.  After 15 - 20 minutes, I can start it.  How do I disable this system?  I saw this answer below, but the answer looked incomplete?

"Answer
All right Marc, this is what I know...
...Normally, you would insert the key in
the drivers door, turn left, then right
to disarm and reset it. If yours is malfunctioning,
you can disable it for good by doing the following:

The FACTORY ALARM DISARM WIRE IS
lt.green |-|in the drivers kick,
Also found in the purple plug of the BCM.
The BCM is located behind the drivers side
of the dash. The plugs on the BCM face
towards the rear of the vehicle.

Once Located, splice into this wire with
a simular guage wire, and put it to
a solid chassis ground. This terminates
the alarm functions entirely.

However, at this point, this car would be exceedingly
easy to steel, so I suggest you get an aftermarket
alarm system to protect it from here on in.

Have a good day.

ALARMTEK
CARALARMSTORE.com"

Thanks
Bruce  

Answer
No that was complete. But a technician might have to be the
one that gets in there and affects the repair if you
are unsure.

The other trouble is the passlock II if it's
engaging for no reason. This is also a dealership
fix. I am betting that the removal of the old system
could have caused this issue, but again, GM
should inspect and reset the systems from here
on out. Let the pro's do they're thing here for
the best results.

A.