2000 Blazer Keyless Entry

I have a 2000 Blazer LS without keyless entry, I have read that you can buy a GM module that plugs into something under the dash? Where is this plug and what GM module would i need to buy? I have installed GM Keyless entry and alarm systems before but I just had to wire into the cars electrical system. Any information would help, thanks!

Get an aftermarket keyless entry system from Avital or something along those lines.

Cheaper and just as functional.

I want a GM Keyless entry, is there a system that I can buy that I can plug right in , instead of wiring into the cars electricals? I have done that already before with a GM keyless entry system (wire it into cars electricals)