im trying to make it so you step in a location to make the siege tank next to you change to an enemy, and will start firing at you, but every time i test it, the tank goes back into tank mode. i disabled the siege mode upgrade for the player who recieves the tank. is there something i did wrong? or any other way to force a tank to stay sieged?

Disabling a technology in use by a computer is useless. They can and will unsiege and unburrow whenever they want because they're mean jerks. To my knowledge, the only way to keep a tank in siege mode is to manipulate the AI.

For example, tanks unsiege when the enemy units are inside of its range and the tank has no target. A solution for this would be to give the tank to an extended player, preferably p12 (neutral) to stop the AI from causing the tank to unsiege. If there's only a few tanks, this can be done by making appropriate sized locations on said tanks. The level of difficulty of this task greatly depends on the theme of your map.

There are cruder but easier methods as well. You can detect if there's a siege tank in tank mode, and then center a location on said tank, remove it and create a new tank in siege mode. This, of course, ruins any HP plans you may have for the tank.

It's another one of Blizzard's wonderful unit AIs and is totally ruining my Desert Strike map.
Afaik you can't do anything against it apart from creating the tank there instead of giving/allying it (not safe, you'll have to try if it works for you) or, if that's possible in your case use Hero tanks. They will always stay sieged, even when attacked by melee.

ill definately use hero tanks then. im trying to make a series of puzzles resembling the jailbreak maps and the tanks only come into play at one small part. thanks