I need to know if my 99 pontaic sunfire has antitheft device.

1.1mm

The security, antitheft, or passlock light is a visual indication that something in the car's antitheft system is failing. In most GM cars and trucks there is a hidden system that most people are unaware even exists. From the moment you put your key in the ignition, there begins a constant line of communication between your key's security chip or transponder, to the ignition's lock cylinder, and then to the car's TDM (Theft Deterrent Module). These 3 parts are in CONSTANT communication. If the key is in the ignition, then these parts are sending signals to each other. The security light illuminates when that signal gets broken, even just for a second. When the signal breaks, the car misinterperates this as an attempt at theft and goes into antitheft mode. The car thinks its being stolen or hotwired because it is not getting that signal from YOUR specific key. This is why the security light turns on and shuts down your vehicle.
This link may help you find ways to bypass this or fix it yourself.
http://vatspasslockpasskeysecurityhelp.yolasite.com/

Remember that these car's the Passlock antitheft system. If you replace the ignition, you need to make sure it is compatible with your antitheft system and will need to use the transponder key like before. This can be a much bigger project than you think. This link explains the antitheft

http://vatspasslockpasskeysecurityhelp.yolasite.com/

Might not be the starter. Might be the antitheft system. Read thru this link for subpoenas and solutions.
http://vatspasslockpasskeysecurityhelp.yolasite.com/

you will find it on the frone side of the trans behind the rad

No, the 1995 PCM (computer) is an OBD1 type, the 1999 PCM is an OBD2 type.

Under your hood there is a box that looks like a fuse box. It contains relays. Replace the one marked horn.

Complete upper dash pad comes off and cluster comes out from the top.

CLICK HERE

Thanks for using FixYa - a FixYa rating is appreciated for answering your FREE question.